It won't look same as the storyboard I uploaded. The butterflies fly following the path so It doesn't look like flock, It looks like thin line of butterflies. I tried to make them as flock but it looked a bit scary. So I changed to make their path as narrow.
30 March 2011
Final work : Compositing Flower, Sky and ButterflyFlow
I imported Sky to Flower scene and tried to import ButterflyFlow as well, but my maya kept crashing whenever I import ButterflyFlow. To solve the problem, I export the camera path from ButterflyFlow and import only the camera to Flower scene. Whole range of video is 500 frame. From 1 to 300 frame, I only rendered Flower scene and from 301 to 500 frame, rendered separately Flower scene and ButterflyFlow scene.
It won't look same as the storyboard I uploaded. The butterflies fly following the path so It doesn't look like flock, It looks like thin line of butterflies. I tried to make them as flock but it looked a bit scary. So I changed to make their path as narrow.
It won't look same as the storyboard I uploaded. The butterflies fly following the path so It doesn't look like flock, It looks like thin line of butterflies. I tried to make them as flock but it looked a bit scary. So I changed to make their path as narrow.
17 March 2011
Particle Example 8 : Realistic Cloud
You wouldn't see any small particle elements in this tutorial. This post will be about making realistic clouds using particle expression. This is for the sky environment that I made for Post Production Project.
1. Set the Dynamics menu set, select Fluid Effects - Create 3D container - Option box.
Set the following options, Apply.
Resolution X, Y, Z : 50, 5, 50
Size X, Y, Z : 50, 5, 50
2. Go to Attribute Editor - Contents Method.
Density : Off(zero)
Velocity : Off(zero)
Temperatur : Off(zero)
3. Scroll down and set the values, inputs and colours as below.
4. Check Texture Incandescence and set values as below.
5. To animate the clouds, Go to the Texture attribute under attribute editor.
Right mouse button click on the Z axis of Texture Origin, select Create New Expression.
Type in
fluidShape1.textureOriginZ = time*0.2;
6. Playback the animation.
7. Play around with implode. As value of implode increases, clouds seem to collide in the middle. Maybe they can be used as explosion.
1. Set the Dynamics menu set, select Fluid Effects - Create 3D container - Option box.
Set the following options, Apply.
Resolution X, Y, Z : 50, 5, 50
Size X, Y, Z : 50, 5, 50
2. Go to Attribute Editor - Contents Method.
Density : Off(zero)
Velocity : Off(zero)
Temperatur : Off(zero)
3. Scroll down and set the values, inputs and colours as below.
4. Check Texture Incandescence and set values as below.
 |
| View from below |
5. To animate the clouds, Go to the Texture attribute under attribute editor.
Right mouse button click on the Z axis of Texture Origin, select Create New Expression.
Type in
fluidShape1.textureOriginZ = time*0.2;
6. Playback the animation.
7. Play around with implode. As value of implode increases, clouds seem to collide in the middle. Maybe they can be used as explosion.
 |
| Implode = 0 |
 |
| Implode = 1 |
 | |
| Implode = 2 |
 | |
| implode = 3 |
Reference
- http://www.sharecg.com/v/5501/browse/Text-Entry-Tutorial/Making-Realistic-looking-Clouds-In-Maya
13 March 2011
Combination Example : Flow and Particle Expression
To make the scene that the butterfly flying up from opening flower, I came up an idea using particle expressions we have been through. Particle Instancing is the key element of this scene because it can make the bunch of flying butterflies. I will connect the particle instance to the flow so the butterflies can emit following the guide funnel. It is not as complicate as it sounds.
First, we will make the Flow which will be the guide funnel for butterflies.
1. Create new scene. Create - EP Curve Tool and creat a curve as below picture in the front
view.
2. Name the curve to butterflyCurve. With the curve selected and select Create Deformer -
Lattice - Option box in the Animation menu set. Set the following and press Create.
Divisions : 5, 9, 2
Autoparent to Selection : On
3. Select the ffd1Lattice node, Right mouse click on it and select Lattice Point. Select the top
three rows of lattice points.
4. Select Deform - Create Cluster - Option box. Check the Relative Mode on. Create.
Repeat this step to create two more clusters.
5. Select the three clusters in the outliner, then Shift - select the butterflyCurve. Press P to parent
the clusters to the curve.
6. Select tornadoCurve. At this time, butterflies are emitting out from the flower
so we won't keyframe translations.
7. Select butterflyCurveShape by pressing ↓key on the keyboard.
8. Change to Dynamics menu set, select Effects - Create Curve Flow - Option box.
Set the following and Create.
Flow Group Name : butterflyFlow
Num Control Sefments : 6
Particle Lifespan : 3
Goal Weight : 0.5
9. Playback the animation.
10. Select the control_Circle_6 which is at the top of butterflyCurve and scale up the circle.
Scale up the lower circles as look like below picture.
11. Select the tornadoFlow and set Display Thickness on in the channel box. You will see
the outline of butterfly funnel shape. Control the scale until you get the shape you want
and set Display Thickness off again.
15. Select the butterflyFlow_particles, go to Fields - Vortex - Option box. Set the following.
Create.
Magnitude : 10
Attenuation : 0
16. Parent the vortex field to butterflyCurve.
17. Select the butterflyCurveShape, Shift - select the vortex field. It will be easy to select in
outliner. Select Fields - Use Selected as Source of Field.
18. Select vortex field, set Apply Per Vertex to On in the channel box. It will make every
point on the curve emit field force.
Now, we will connect butterfly to flow.
19. Make simple butterfly model and duplicate 8 times. Arrange them on the Y axis.
Hide the original butterfly. Rotate the wings of each duplicates as below.
20. Select butterfly1 through butterfly8 in order in the Outliner.
Select Particles - Instancer (Replacement) - Option box. Set the following options. Create.
Particle Instancer Name : butterflyInstancer
Cycle : Se1uential
Cycle Step Size : 1
Make sure the butterfly1 to butterfly8 are in the Instanced Objects.
21. Hide butterflyParticles. Playback the animation.
First, we will make the Flow which will be the guide funnel for butterflies.
1. Create new scene. Create - EP Curve Tool and creat a curve as below picture in the front
view.
2. Name the curve to butterflyCurve. With the curve selected and select Create Deformer -
Lattice - Option box in the Animation menu set. Set the following and press Create.
Divisions : 5, 9, 2
Autoparent to Selection : On
3. Select the ffd1Lattice node, Right mouse click on it and select Lattice Point. Select the top
three rows of lattice points.
4. Select Deform - Create Cluster - Option box. Check the Relative Mode on. Create.
Repeat this step to create two more clusters.
5. Select the three clusters in the outliner, then Shift - select the butterflyCurve. Press P to parent
the clusters to the curve.
6. Select tornadoCurve. At this time, butterflies are emitting out from the flower
so we won't keyframe translations.
7. Select butterflyCurveShape by pressing ↓key on the keyboard.
8. Change to Dynamics menu set, select Effects - Create Curve Flow - Option box.
Set the following and Create.
Flow Group Name : butterflyFlow
Num Control Sefments : 6
Particle Lifespan : 3
Goal Weight : 0.5
9. Playback the animation.
10. Select the control_Circle_6 which is at the top of butterflyCurve and scale up the circle.
Scale up the lower circles as look like below picture.
11. Select the tornadoFlow and set Display Thickness on in the channel box. You will see
the outline of butterfly funnel shape. Control the scale until you get the shape you want
and set Display Thickness off again.
15. Select the butterflyFlow_particles, go to Fields - Vortex - Option box. Set the following.
Create.
Magnitude : 10
Attenuation : 0
16. Parent the vortex field to butterflyCurve.
17. Select the butterflyCurveShape, Shift - select the vortex field. It will be easy to select in
outliner. Select Fields - Use Selected as Source of Field.
18. Select vortex field, set Apply Per Vertex to On in the channel box. It will make every
point on the curve emit field force.
Now, we will connect butterfly to flow.
19. Make simple butterfly model and duplicate 8 times. Arrange them on the Y axis.
Hide the original butterfly. Rotate the wings of each duplicates as below.
20. Select butterfly1 through butterfly8 in order in the Outliner.
Select Particles - Instancer (Replacement) - Option box. Set the following options. Create.
Particle Instancer Name : butterflyInstancer
Cycle : Se1uential
Cycle Step Size : 1
Make sure the butterfly1 to butterfly8 are in the Instanced Objects.
21. Hide butterflyParticles. Playback the animation.
Reference
- Autodesk Maya 2011, 2010. Autodesk Maya Online Help : Introduction. [online] Available at : < file:///Applications/Autodesk/maya2011/docs/Maya2011/en_US/index.html?url=./files/GS_Introduction.htm,topicNumber=d0e1838 > [Accessed 25 February 2011].
- Marc-André Guindon., 2005. Learning Maya 7 : The Special Effects Handbook. Unknown: Sybex
12 March 2011
Particle Example 7 : Particle Instancing Pt.2
In the Particle Instancing Pt.1, we made a bunch of flies. It moved in the same fashion and looked robotic. This time we will make Instance cycling to randomly animate a flock of flies.
1. Create new scene and make the fly same as Pt.1. or you can use the same fly from Pt.1.
Select the fly group in the outliner. Duplicate the group 8 times. Arrange them on the Y axis.
Make sure you do not mess the flies geometry while moving them. It will cause offsetting
from the particles during instancing.
2. Hide the original fly. Rotate the wings of each duplicated flies as below.
3. Select Particles - Particle Tool - Option box. Setting as following and create.
Particle name : flyParticles
Number of particles : 20
Maximum radius : 40
4. Select fly1 through fly 8 in order in Outliner. The order will determine the cycling
order used by the instancer.
5. Select Particles - Instancer (Replacement) - Option box. Set as the following and Create.
Particle Instancer Name : flyInstancer
Cycle : Sequential
Cycle Step Size : 1
6. Hide fly1 through fly8. Playback the animation. All flies move in the same fashion.
7. Select flyParticles and open the Attribute Editor. Go to Add Dynamic Attribute - General.
Under the new tab, set the following options.
Attribute Name : customAge
Data Type : Float
Attribute Type : Per Particle (Array)
Add Initial State Attribute : ON
8. Right mouse click on customAge Attribute and select Runtime Expression Before Dynamics.
if (particleId ==0)
customAge = age;
else if (particleId ==1)
customAge = age * 0.5;
else if ((particleId % 2 == 0) && (particleId % 3 == 0))
customAge = age * 0.25 * particleId / 4;
else if (particleId % 2 == 0)
customAge = age* 0.4 * particleId / 4;
else if (particleId % 3 == 0)
customAge = age * 0.35 * particleId / 4;
else
customAge = age * 0.2 * particleId / 4;
9. Select flyParticles, set Particle Render Type to Numeric. You can see which particle
will be affected by which portion of the expression.
10. Go to flyParticles' Attribute Editor - Instancer (Geometry Replacement) - Cycle Option
- Age pull down menu, select customAge.
11. At the flyParticles Attribute Editor - Add Dynamic Attribute - General. Under the
new tab, set the following options.
Attribute Name : startPick
Data Type : Float
Attribute Type : Per Particle (Array)
Add Initial State Attribute : ON
12. Add creation expression to startPick attribute.
if ( particleId == 0 )
startPick = 0;
else if ( particleId ==1 )
startPick = 1;
else if ( ( particleId % 2 == 0 ) && ( particleId % 3 == 0 ))
startPick = 2;
else if ( particleId % 2 == 0 )
startPick = 3;
else if ( particleId % 3 == 0 )
startPick = 4;
else
startPick = 5;
14. Playback the animation.
1. Create new scene and make the fly same as Pt.1. or you can use the same fly from Pt.1.
Select the fly group in the outliner. Duplicate the group 8 times. Arrange them on the Y axis.
Make sure you do not mess the flies geometry while moving them. It will cause offsetting
from the particles during instancing.
2. Hide the original fly. Rotate the wings of each duplicated flies as below.
3. Select Particles - Particle Tool - Option box. Setting as following and create.
Particle name : flyParticles
Number of particles : 20
Maximum radius : 40
4. Select fly1 through fly 8 in order in Outliner. The order will determine the cycling
order used by the instancer.
5. Select Particles - Instancer (Replacement) - Option box. Set as the following and Create.
Particle Instancer Name : flyInstancer
Cycle : Sequential
Cycle Step Size : 1
- A cycle setting of Sequential causes the instancer to cycle through the object indices in sequence rather than not using any cycling at all. A Cycle Step Size of 1 causes the instancer to display each object index for 1 frame before changing to the next item in the list.
6. Hide fly1 through fly8. Playback the animation. All flies move in the same fashion.
7. Select flyParticles and open the Attribute Editor. Go to Add Dynamic Attribute - General.
Under the new tab, set the following options.
Attribute Name : customAge
Data Type : Float
Attribute Type : Per Particle (Array)
Add Initial State Attribute : ON
8. Right mouse click on customAge Attribute and select Runtime Expression Before Dynamics.
if (particleId ==0)
customAge = age;
else if (particleId ==1)
customAge = age * 0.5;
else if ((particleId % 2 == 0) && (particleId % 3 == 0))
customAge = age * 0.25 * particleId / 4;
else if (particleId % 2 == 0)
customAge = age* 0.4 * particleId / 4;
else if (particleId % 3 == 0)
customAge = age * 0.35 * particleId / 4;
else
customAge = age * 0.2 * particleId / 4;
- Each particle has unique particleId. By using the particleId, it controls this duration on a per particle basis. This is accomplished by multiplying the particleId by the age and saving the result in Age control we made above.
9. Select flyParticles, set Particle Render Type to Numeric. You can see which particle
will be affected by which portion of the expression.
10. Go to flyParticles' Attribute Editor - Instancer (Geometry Replacement) - Cycle Option
- Age pull down menu, select customAge.
11. At the flyParticles Attribute Editor - Add Dynamic Attribute - General. Under the
new tab, set the following options.
Attribute Name : startPick
Data Type : Float
Attribute Type : Per Particle (Array)
Add Initial State Attribute : ON
12. Add creation expression to startPick attribute.
if ( particleId == 0 )
startPick = 0;
else if ( particleId ==1 )
startPick = 1;
else if ( ( particleId % 2 == 0 ) && ( particleId % 3 == 0 ))
startPick = 2;
else if ( particleId % 2 == 0 )
startPick = 3;
else if ( particleId % 3 == 0 )
startPick = 4;
else
startPick = 5;
- After step 11, all flies begin their sequence at their fly1 position. You can change the object index the sequence starts on by setting the CycleStartObject attribute in the instancer. To do this, you will create another custom attribute (above). It controls CycleStartObject on a per particle basis.
14. Playback the animation.
Reference
- Autodesk Maya 2011, 2010. Autodesk Maya Online Help : Introduction. [online] Available at : < file:///Applications/Autodesk/maya2011/docs/Maya2011/en_US/index.html?url=./files/GS_Introduction.htm,topicNumber=d0e1838 > [Accessed 25 February 2011].
- Marc-André Guindon., 2005. Learning Maya 7 : The Special Effects Handbook. Unknown: Sybex
09 March 2011
Particle Example 6 : Particle Instancing Pt.1
As I cleared in the second post, I was looking for the way connecting animated object to particles node. I found I can make the scene by using Particle Instancing. Although, Instancing is like connecting the master object with particles so I need to animate particles as well. However, it will save a lot of time than animating bunch of butterflies individually. In this post, the focus will be on instancing object with particles first.
Instancing?
An instance is similar to a duplicated object but the difference is, it is not actual object. Let's say you are in a room surrounded by 100 mirrors. If you lift one leg, many of you in the mirror will lift one leg too. But it doesn't mean every you in 100 mirrors are "actual" you.
An instance contains no actual surface information, but is just a redrawn version of an original object. The original object acts like a master to all of its instances like you in the mirror room. Instances will be updated as the original is updated on all shading and surface characteristics.
Instances contain less information than duplicates so they can be handled and redrawn faster.
Particle Instancing
Particle instancing is the process of using the position and behaviour of particles to control the position and behaviour of instanced geometry. Although some complex results can be obtained using particle instancing, it is important not to interpret it as a full-featured behaviour animation system or flocking system. There are no behavioural relationships between the individual instanced elements.
1. Create new scene. Make any fly looking object with polyCylinder and polyPlane, it doesn't need to be descent looking. If you already have a model, use it. I made the model like below, renamed and made a group.
2. Animate and keyframe both wings frame by frame.
Frame 1 : wings down
Frame 2 : wings straight
Frame 3 : wings up
Frame 4 : wings straight
Frame 5 : wings down
3. Select both wings, go to Window - Animation Editors - Graph Editor.
Set the Pre-Infinity and Post-Infinity to Cycle. It will make the fly flap its wings repeatedly.
4. Select Particle - Particle Tool - Option box. Set the following.
Particle Name : flyParticles
Conserve : 1
Create Particle Grid : On
Particle Spacing : 12
Placement : With Text Fields
Minimum Corner : -25, 0, -25
Maximum Corner : 25, 0, 25
Click anywhere in the viewport and press Enter.
5. Add below expressions as creation expression in the position attribute under Per Particle
Attributes of flyParticles.
float $randY = rand (-3,3);
float $randXZ = rand (-1, 1);
vector $offset = <<$randXZ , $randY, $randXZ>>;
position = position + $offset;
6. After create the expression, Rewind the time slider to offset the particles.
7. With theflyParticles selected, select Solvers - Initial State - Set for Selected.
Delete the creation expression.
8. Select the fly group in the outliner. Select Particles - Instancer (Replacement) - Option box.
Set Particle Instancer Name to flyInstanced. Make sure the fly is the only listed object
in the Instanced Objects list. Press Create.
9. Select the original fly group and hide it by pressing Ctrl+h.
10. Open the flyParticlesShape attribute editor. Select Add Dynamic Attributes - General.
Set the following under the New tab and press OK.
Attribute Name : flyScaler
Data Type : Vector
Attribute Type : Per Particle Array
Add Initial State Attribute : ON
11. Right mouse click onto the box next to flyScaler in the Per Particle Attribute,
select Creation Expression. Type following expression and Create.
$rand = rand (0.4, 1.5);
flyScaler = <<$rand, $rand, $rand>>;
12. Select flyParticleShape, expand the Instancer (Geometry Replacement) tab.
Under General Option, Set Scale to flyScale.
13. Delete the flyScale creation expression. Select Solvers - Initial State - Set for Selected.
14. Select particle object and select Fields - Uniform. Set the following settings
Direction X, Y, Z : 1, 0, 0
Magnitude : 15
Attenuation : 0
15. Playback the animation.
Analyze Expression
1. Randomly offset the particles
float $randY = rand (-3,3) :
Get random value between -3 and 3 into float type variable called $randY
float $randXZ = rand (-1, 1) :
Get random value between -1 and 1 into float type variable called $randXZ
vector $offset = <<$randXZ, $randY, $randXZ >> :
vector type $offset is evaluated by the components $randXZ, $randY, $randXZ
position = position + $offset :
The value of position is assigned by the sum of default position value and $offset
2. flyScaler
$rand = rand (0.4, 1.5) :
$rand's value is evaluated by random number between 0.4 and 1.5 for each particle
flyScaler = <<$rand, $rand, $rand>>;
Value of flyScaler is assigned by the vector value which has $rand as X, Y, Z components.
Instancing?
An instance is similar to a duplicated object but the difference is, it is not actual object. Let's say you are in a room surrounded by 100 mirrors. If you lift one leg, many of you in the mirror will lift one leg too. But it doesn't mean every you in 100 mirrors are "actual" you.
An instance contains no actual surface information, but is just a redrawn version of an original object. The original object acts like a master to all of its instances like you in the mirror room. Instances will be updated as the original is updated on all shading and surface characteristics.
Instances contain less information than duplicates so they can be handled and redrawn faster.
Particle Instancing
Particle instancing is the process of using the position and behaviour of particles to control the position and behaviour of instanced geometry. Although some complex results can be obtained using particle instancing, it is important not to interpret it as a full-featured behaviour animation system or flocking system. There are no behavioural relationships between the individual instanced elements.
1. Create new scene. Make any fly looking object with polyCylinder and polyPlane, it doesn't need to be descent looking. If you already have a model, use it. I made the model like below, renamed and made a group.
2. Animate and keyframe both wings frame by frame.
Frame 1 : wings down
Frame 2 : wings straight
Frame 3 : wings up
Frame 4 : wings straight
Frame 5 : wings down
3. Select both wings, go to Window - Animation Editors - Graph Editor.
Set the Pre-Infinity and Post-Infinity to Cycle. It will make the fly flap its wings repeatedly.
4. Select Particle - Particle Tool - Option box. Set the following.
Particle Name : flyParticles
Conserve : 1
Create Particle Grid : On
Particle Spacing : 12
Placement : With Text Fields
Minimum Corner : -25, 0, -25
Maximum Corner : 25, 0, 25
Click anywhere in the viewport and press Enter.
5. Add below expressions as creation expression in the position attribute under Per Particle
Attributes of flyParticles.
float $randY = rand (-3,3);
float $randXZ = rand (-1, 1);
vector $offset = <<$randXZ , $randY, $randXZ>>;
position = position + $offset;
6. After create the expression, Rewind the time slider to offset the particles.
7. With theflyParticles selected, select Solvers - Initial State - Set for Selected.
Delete the creation expression.
8. Select the fly group in the outliner. Select Particles - Instancer (Replacement) - Option box.
Set Particle Instancer Name to flyInstanced. Make sure the fly is the only listed object
in the Instanced Objects list. Press Create.
9. Select the original fly group and hide it by pressing Ctrl+h.
10. Open the flyParticlesShape attribute editor. Select Add Dynamic Attributes - General.
Set the following under the New tab and press OK.
Attribute Name : flyScaler
Data Type : Vector
Attribute Type : Per Particle Array
Add Initial State Attribute : ON
11. Right mouse click onto the box next to flyScaler in the Per Particle Attribute,
select Creation Expression. Type following expression and Create.
$rand = rand (0.4, 1.5);
flyScaler = <<$rand, $rand, $rand>>;
12. Select flyParticleShape, expand the Instancer (Geometry Replacement) tab.
Under General Option, Set Scale to flyScale.
13. Delete the flyScale creation expression. Select Solvers - Initial State - Set for Selected.
14. Select particle object and select Fields - Uniform. Set the following settings
Direction X, Y, Z : 1, 0, 0
Magnitude : 15
Attenuation : 0
15. Playback the animation.
Analyze Expression
1. Randomly offset the particles
float $randY = rand (-3,3) :
Get random value between -3 and 3 into float type variable called $randY
float $randXZ = rand (-1, 1) :
Get random value between -1 and 1 into float type variable called $randXZ
vector $offset = <<$randXZ, $randY, $randXZ >> :
vector type $offset is evaluated by the components $randXZ, $randY, $randXZ
position = position + $offset :
The value of position is assigned by the sum of default position value and $offset
2. flyScaler
$rand = rand (0.4, 1.5) :
$rand's value is evaluated by random number between 0.4 and 1.5 for each particle
flyScaler = <<$rand, $rand, $rand>>;
Value of flyScaler is assigned by the vector value which has $rand as X, Y, Z components.
Reference
- Autodesk Maya 2011, 2010. Autodesk Maya Online Help : Introduction. [online] Available at : < file:///Applications/Autodesk/maya2011/docs/Maya2011/en_US/index.html?url=./files/GS_Introduction.htm,topicNumber=d0e1838 > [Accessed 25 February 2011].
- Marc-André Guindon., 2005. Learning Maya 7 : The Special Effects Handbook. Unknown: Sybex
08 March 2011
Particle Example 5 : Flow
In this tutorial, we will make a tornado. Not like earlier examples, it doesn't have any expressions. It will be easier to follow!
1. Create new scene. Create - EP Curve Tool and creat a curve as below picture in the front
view.
2. Name the curve to tornadoCurve. With the curve selected and select Create Deformer -
Lattice - Option box in the Animation menu set. Set the following and press Create.
Divisions : 5, 9, 2
Autoparent to Selection : On
3. Select the ffd1Lattice node, Right mouse click on it and select Lattice Point. Select the top
three rows of lattice points.
4. Select Deform - Create Cluster - Option box. Check the Relative Mode on. Create.
Repeat this step to create two more clusters.
5. Select the three clusters in the outliner, then Shift - select the tornadoCurve. Press P to parent
the clusters to the curve.
6. Select tornadoCurve. Set the time slider at frame 1. Move tornadoCurve to -12, 0, 12
(Translate x, y, z). Press Shift+w to keyframe the translations.
7. Move the time slider to 110 and set another keyframe by pressing Shift+w.
8. At frame 160, move the tornadoCurve to 0, 0, 0 and press Shift+w.
9. At frame 300, move the tornadoCurve to -12, 0, -12 and press Shift+w.
10. Select tornadoCurveShape by pressing ↓key on the keyboard.
11. Change to Dynamics menu set, select Effects - Create Curve Flow - Option box.
Set the following and Create.
Flow Group Name : tornadoFlow
Num Control Sefments : 6
Particle Lifespan : 3
Goal Weight : 0.5
12. Playback the animation.
13. Select the control_Circle_6 which is at the top of tornadoCurve and scale up the circle.
Scale up the lower circles as look like below picture.
14. Select the tornadoFlow and set Display Thickness on in the channel box. You will see
the outline of tornado funnel shape. Control the scale until you get the shape you want
and set Display Thickness off again.
15. Select the tornadoFlow_particles, go to Fields - Vortex - Option box. Set the following.
Create.
Magnitude : 10
Attenuation : 0
16. Parent the vortex field to tornadoCurve.
17. Select the tornadoCurveShape, Shift - select the vortex field. It will be easy to select in
outliner. Select Fields - Use Selected as Source of Field.
18. Select vortex field, set Apply Per Vertex to On in the channel box. It will make every
point on the curve emit field force.
19. Select the tornadoFlow_particle and switch the Particle Render Type to Cloud(s/w)
in the channel box.
20. Go to Attribute Editor - Add Dynamic Attributes - General - under Particle tap - radiusPP.
Add radiusPP.
21. Right mouse click on the box next to radiusPP in Per Particle Attribute. Select Create Ramp.
Right mouse click again and select arrayMapper - Edit Ramp. Set the values of the ramp :
Radius starts at 0.1 and dies at 0.9.
22. Play the animation. Render the scene so that the tornado look blue.
1. Create new scene. Create - EP Curve Tool and creat a curve as below picture in the front
view.
2. Name the curve to tornadoCurve. With the curve selected and select Create Deformer -
Lattice - Option box in the Animation menu set. Set the following and press Create.
Divisions : 5, 9, 2
Autoparent to Selection : On
3. Select the ffd1Lattice node, Right mouse click on it and select Lattice Point. Select the top
three rows of lattice points.
4. Select Deform - Create Cluster - Option box. Check the Relative Mode on. Create.
Repeat this step to create two more clusters.
5. Select the three clusters in the outliner, then Shift - select the tornadoCurve. Press P to parent
the clusters to the curve.
6. Select tornadoCurve. Set the time slider at frame 1. Move tornadoCurve to -12, 0, 12
(Translate x, y, z). Press Shift+w to keyframe the translations.
7. Move the time slider to 110 and set another keyframe by pressing Shift+w.
8. At frame 160, move the tornadoCurve to 0, 0, 0 and press Shift+w.
9. At frame 300, move the tornadoCurve to -12, 0, -12 and press Shift+w.
10. Select tornadoCurveShape by pressing ↓key on the keyboard.
11. Change to Dynamics menu set, select Effects - Create Curve Flow - Option box.
Set the following and Create.
Flow Group Name : tornadoFlow
Num Control Sefments : 6
Particle Lifespan : 3
Goal Weight : 0.5
12. Playback the animation.
13. Select the control_Circle_6 which is at the top of tornadoCurve and scale up the circle.
Scale up the lower circles as look like below picture.
14. Select the tornadoFlow and set Display Thickness on in the channel box. You will see
the outline of tornado funnel shape. Control the scale until you get the shape you want
and set Display Thickness off again.
15. Select the tornadoFlow_particles, go to Fields - Vortex - Option box. Set the following.
Create.
Magnitude : 10
Attenuation : 0
16. Parent the vortex field to tornadoCurve.
17. Select the tornadoCurveShape, Shift - select the vortex field. It will be easy to select in
outliner. Select Fields - Use Selected as Source of Field.
18. Select vortex field, set Apply Per Vertex to On in the channel box. It will make every
point on the curve emit field force.
19. Select the tornadoFlow_particle and switch the Particle Render Type to Cloud(s/w)
in the channel box.
20. Go to Attribute Editor - Add Dynamic Attributes - General - under Particle tap - radiusPP.
Add radiusPP.
21. Right mouse click on the box next to radiusPP in Per Particle Attribute. Select Create Ramp.
Right mouse click again and select arrayMapper - Edit Ramp. Set the values of the ramp :
Radius starts at 0.1 and dies at 0.9.
22. Play the animation. Render the scene so that the tornado look blue.
Reference
- Autodesk Maya 2011, 2010. Autodesk Maya Online Help : Introduction. [online] Available at : < file:///Applications/Autodesk/maya2011/docs/Maya2011/en_US/index.html?url=./files/GS_Introduction.htm,topicNumber=d0e1838 > [Accessed 25 February 2011].
- Marc-André Guindon., 2005. Learning Maya 7 : The Special Effects Handbook. Unknown: Sybex
03 March 2011
Per Particle Attributes
After I uploaded emitter tutorial, I needed to define what "Per Particle (array) Attribute" is.
- Per Particle Attribute allows each particle to store its own value for a given attribute. That is why most expressions are applied to Per Particle Attributes. Per Particle Attribute can control each particles in object so that it can create complicated and variable particle effects. However, Per Particle Attribute cannot be keyframed, be used with other expression and it should be used only in particle expression.
- Some attributes has PP at the end their names. PP means Per Particle so it can be easily distinguished, but remember there are other Per Particle attributes like Position and Velocity which doesn't have PP at the end.
Reference
- Jo Sang Bum., 2002. programming with MAYA MEL & Expression. Seoul: Ahn Dae Sik
- Autodesk Maya 2011, 2010. Autodesk Maya Online Help : Introduction. [online] Available at : < file:///Applications/Autodesk/maya2011/docs/Maya2011/en_US/index.html?url=./files/GS_Introduction.htm,topicNumber=d0e1838 > [Accessed 25 February 2011].
- Marc-André Guindon., 2005. Learning Maya 7 : The Special Effects Handbook. Unknown: Sybex
02 March 2011
Particle Example 4 : Emit Function
There are five different types of emitter.
1. Create new scene. Select Particles - Create Emitter - Option box.
2. Settings for emitter
Name : primaryEmitter
Emitter Type : Directional
Rate : 100
Direction : 0, 1, 0
Spread : 0.25
Speed : 10
3. Select particle in the outliner. Change the name to primaryParticles.
Open the attribute editor - primaryParticlesShape and change the values as below.
Name : primaryParticles
Particle Render Type : Spheres
Radius 0.2
Lifespan Mode : lifespanPP only
4. Type the following line in the command line and press Enter.
It creates an empty particle object.
particle -n secondaryParticles;
5. Select the secondaryParticles in the outliner and change as below in the channel box.
Particle Render Type : Multi-Streak
Lifespan Mode : lifespanPP only
6. Select primaryParticles. Select Fields - Gravity.
7. Right mouse button click the box next to the lifespanPP attribute under primaryParticles.
Add Runtime expression before dynamics. Because the particles is keep changing its
position after its birth from emitter. Click Create.
$pos = position;
$vel = velocity;
if ($vel.y < 0)
{
lifespanPP = 0;
emit -object secondaryParticles -position ($pos.x) ($pos.y) ($pos.z)
-at velocity -vectorValue ($vel.x) ($vel.y) ($vel.z);
}
★ If the expression worked well, congratulation. When I typed in the expression, I had
an error message saying "Illegal extension on an expression of type float."
So I corrected the components of $pos and $vel like below. "position" and "velocity"
are value of pribaryParticles, it directly access to the position and velocity value.
If you had same error message like me, try change the components' names. ★
8. Set the time range as approximately 500 frames and playback.
Now, we will change the colour of multi-streak.
9. Add an rgbPP attribute to secondaryParticles as we did earlier tutorial.
Attribute Editor - Per Particle (Array) Attribute - select color - add "per particle"
10. Go to the Runtime expression before dynamics on primaryParticles and add some lines as below.
$pos = position;
$vel = velocity;
$col = sphrand(1);
if ($vel.y < 0)
{
lifespanPP = 0;
emit -object secondaryParticles -position ($pos.x) ($pos.y) ($pos.z)
-at velocity -vectorValue ($vel.x) ($vel.y) ($vel.z)
-at rgbPP -vectorValue ($col.x)($col.y)($col.z);
}
11. Click Edit and playback the animation.
Analyze Expression
if ($vel.y < 0) : If primaryParticle's velocity Y value is smaller than 0.
- Omni : Omnidirectional point emitter. particle emits in all directions.
- Directional : Directional point emitter. Particles emit in the direction you specify with the Direction X, Y, and Z attributes.
- Surface : It emits particle from randomly distributed positions on or near a NURBS or polygonal surface. When you emit from an object, the emitter is a surface emitter.
- Curve : It emits particle from randomly distributed positions on or near a curve.
- Volume : It emits particle from a closed volume. You pick the shape from the Volume Shape option. Make sure the emitter is bigger than one voxel when you select volume.
1. Create new scene. Select Particles - Create Emitter - Option box.
2. Settings for emitter
Name : primaryEmitter
Emitter Type : Directional
Rate : 100
Direction : 0, 1, 0
Spread : 0.25
Speed : 10
3. Select particle in the outliner. Change the name to primaryParticles.
Open the attribute editor - primaryParticlesShape and change the values as below.
Name : primaryParticles
Particle Render Type : Spheres
Radius 0.2
Lifespan Mode : lifespanPP only
4. Type the following line in the command line and press Enter.
It creates an empty particle object.
particle -n secondaryParticles;
5. Select the secondaryParticles in the outliner and change as below in the channel box.
Particle Render Type : Multi-Streak
Lifespan Mode : lifespanPP only
6. Select primaryParticles. Select Fields - Gravity.
7. Right mouse button click the box next to the lifespanPP attribute under primaryParticles.
Add Runtime expression before dynamics. Because the particles is keep changing its
position after its birth from emitter. Click Create.
$pos = position;
$vel = velocity;
if ($vel.y < 0)
{
lifespanPP = 0;
emit -object secondaryParticles -position ($pos.x) ($pos.y) ($pos.z)
-at velocity -vectorValue ($vel.x) ($vel.y) ($vel.z);
}
★ If the expression worked well, congratulation. When I typed in the expression, I had
an error message saying "Illegal extension on an expression of type float."
So I corrected the components of $pos and $vel like below. "position" and "velocity"
are value of pribaryParticles, it directly access to the position and velocity value.
If you had same error message like me, try change the components' names. ★
8. Set the time range as approximately 500 frames and playback.
Now, we will change the colour of multi-streak.
9. Add an rgbPP attribute to secondaryParticles as we did earlier tutorial.
Attribute Editor - Per Particle (Array) Attribute - select color - add "per particle"
10. Go to the Runtime expression before dynamics on primaryParticles and add some lines as below.
$pos = position;
$vel = velocity;
$col = sphrand(1);
if ($vel.y < 0)
{
lifespanPP = 0;
emit -object secondaryParticles -position ($pos.x) ($pos.y) ($pos.z)
-at velocity -vectorValue ($vel.x) ($vel.y) ($vel.z)
-at rgbPP -vectorValue ($col.x)($col.y)($col.z);
}
11. Click Edit and playback the animation.
Analyze Expression
$pos = position;
$vel = velocity;
$col = sphrand(1); - We have made the two variable called $pos and $vel. Each variable contains the value of position and velocity of primaryParticles. 'pos' and 'vel' are short name of position and velocity attributes. Both are vector types : $pos has vector value of position and $vel has vector value of velocity of particle.
- In the expression of colour, the sphrand() function has been used. sphrand is short for 'sphere rand'. sphrand function can specify the range of vector / float type return value. The range of return value has form of sphere or oval. The standard form of sphrand function is sphrand<<x,y,z>> but if you use as sphrand(n), sphrand(1) in this example, it convert to sphrand<<1, 1, 1>> automatically. In this example, sphrand() function returns the value of spheres which has the colour information of Red, Green, Blue.
if ($vel.y < 0) : If primaryParticle's velocity Y value is smaller than 0.
{
lifespanPP = 0; : Set the lifespanPP value as 0.
emit -object secondaryParticles -position ($pos.x) ($pos.y) ($pos.z)
-at velocity -vectorValue ($vel.x) ($vel.y) ($vel.z)
-at rgbPP -vectorValue ($col.x)($col.y)($col.z);
}
- emit : The emit function can set any attribute for a particle, not just its position. It makes emit from selected particle object.
- -object secondaryParticles : Select an object
- -position ($pos.x) ($pos.y) ($pos.z) : emit from secondaryParticles at the position which decided by primaryParticles' position x,y,z.
- -at velocity -vectorValue ($vel.x) ($vel.y) ($vel.z) : Select an attribute of velocity. Get values of the primaryParticles' velocity x,y,z and assembly as secondaryParticles' vector components.
- -at rgbPP -vectorValue ($col.x) ($col.y) ($col.z) : Select an attribute of rgbPP. Get random values from the sphrand(1) and assembly as secondaryParticles' colour components.
Reference
- Autodesk Maya 2011, 2010. Autodesk Maya Online Help :
Introduction. [online] Available at : <
file:///Applications/Autodesk/maya2011/docs/Maya2011/en_US/index.html?url=./files/GS_Introduction.htm,topicNumber=d0e1838
> [Accessed 25 February 2011].
- Marc-André Guindon., 2005. Learning Maya 7 : The Special Effects Handbook. Unknown: Sybex
- http://download.novedge.com/Brands/Alias/Helps/Maya6.5/en_US/MEL/listofparticleattributes.html
27 February 2011
Creation Expression VS Runtime Expression
You can apply creation expression and runtime expression to the particles. It can be used separately and both together at the same time. If you connect expression to ordinary object, you can set expressions to each different attributes, however, you can set creation expression and runtime expression to only one particle bearing no relation to attribute.
Creation expression evaluated only once for each particle when particle is born. If particles came out from emitter, these particles won't be affected by the expression after they born.
1. Create new scene. Select Particle - Particle Tool - Option box. Check Creat particle grid. Click and drag to make particle on to the top view. Press Enter.
2. Go to the particleShape node and scroll down to Add Dynamics Attribute. Click Color and add Per Particle Attribute.
3. Right mouse button click on new RGB PP attribute box and select Creation expression. Enter below expression.
particleShape1.rgbPP = <<rand(1), rand(1), rand(1)>>;
4. Playback the animation. particle's colours look all same in frame 1, 10, 21. This is because the expression evaluated once at the particle birth.
Runtime expression evaluated at least once per particle per frame but not at particle birth. For the same instance as creation expression, particles from emitter will be affected by the expression
even after their birth.
1. Create new scene and repeat 1 and 2 as above example.
2. Right mouse click on to the RGB PP attribute box and click
Runtime expression before dynamics. Enter below expression.
particleShape1.rgbPP = <<rand(1), rand(1), rand(1)>>;
3. Playback the animation. You will see the colour of particles changes each every frames.
Creation expression and Runtime expression using at the same time
1. Go to the rgbPP attribute of above runtime expression example. Right mouse click the box next to the RGBPP and select creation expression. Enter the below expression. Create.
particleShape1.rgbPP = <<1, 1, 0.2>>;
2. Now the particle RGBPP node has two expressions which are Runtime expression before dynamics and Creation expression. Playback the animation. At the frame 1, all particles will be yellow. After frame 2, particles' colour will change every frames.
Creation expression evaluated only once for each particle when particle is born. If particles came out from emitter, these particles won't be affected by the expression after they born.
1. Create new scene. Select Particle - Particle Tool - Option box. Check Creat particle grid. Click and drag to make particle on to the top view. Press Enter.
2. Go to the particleShape node and scroll down to Add Dynamics Attribute. Click Color and add Per Particle Attribute.
3. Right mouse button click on new RGB PP attribute box and select Creation expression. Enter below expression.
particleShape1.rgbPP = <<rand(1), rand(1), rand(1)>>;
4. Playback the animation. particle's colours look all same in frame 1, 10, 21. This is because the expression evaluated once at the particle birth.
 | |
| Frame 1 |
 | |
| Frame 10 |
 | |
| Frame 21 |
Runtime expression evaluated at least once per particle per frame but not at particle birth. For the same instance as creation expression, particles from emitter will be affected by the expression
even after their birth.
1. Create new scene and repeat 1 and 2 as above example.
2. Right mouse click on to the RGB PP attribute box and click
Runtime expression before dynamics. Enter below expression.
particleShape1.rgbPP = <<rand(1), rand(1), rand(1)>>;
3. Playback the animation. You will see the colour of particles changes each every frames.
Creation expression and Runtime expression using at the same time
1. Go to the rgbPP attribute of above runtime expression example. Right mouse click the box next to the RGBPP and select creation expression. Enter the below expression. Create.
particleShape1.rgbPP = <<1, 1, 0.2>>;
2. Now the particle RGBPP node has two expressions which are Runtime expression before dynamics and Creation expression. Playback the animation. At the frame 1, all particles will be yellow. After frame 2, particles' colour will change every frames.
 | |
| Frame 1 |
 | |
| Frame 10 |
 | |
| Frame 21 |
Reference
- Jo Sang Bum., 2002. programming with MAYA MEL & Expression. Seoul: Ahn Dae Sik
- Autodesk Maya 2011, 2010. Autodesk Maya Online Help : Introduction. [online] Available at : < file:///Applications/Autodesk/maya2011/docs/Maya2011/en_US/index.html?url=./files/GS_Introduction.htm,topicNumber=d0e1838 > [Accessed 25 February 2011].
- Marc-André Guindon., 2005. Learning Maya 7 : The Special Effects Handbook. Unknown: Sybex
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