If you want to modify the results of the sketching, remember that you can select, delete, and transform the particles in Point mode as you would any object points.
In addition to creating particles that are emitted from an object, you can sketch particles. Basically, you draw a free-form curve and the particles are created based on the gesture of the stroke you made.
Sketched particles do not simulate and react to forces and obstacles like regular particles because they do not create a simulation operator. You usually add them to an existing particle cloud. However, you can animate the sketched particles’ properties to create changes, like increasing their numbers or the radius over which they’re spread.
Sketching works with snapping, which is particularly useful when painting particles on surfaces (snap to the surface). As well, you can sketch in symmetry mode (click the Sym button in the Transform panel and draw!).
Before you start sketching, you can set up how the resulting particles are created, including which particle type to be used.
To set up for sketching particles
1. Choose Create > Particles > Sketch Particle Setup from the Simulate toolbar.
This opens the default Add Particle operator’s property editor. Changes you make here affect all subsequent particles that you sketch.
2. Set these parameters as you like, as described in Editing the Sketched Particles. Speed is an important parameter to set before drawing because the direction and speed at which you drag the Sketch Particles drawing tool determines the speed of the particles.
To select a particle type to use for sketching
• Right-click any particle type’s icon in the explorer (at the Scene or Project level) and choose Set as Current Particle Type. This particle type will then be used when painting.
This is especially important if you’re sketching new particles that are not associated to an existing cloud. If you’re adding particles to an existing cloud, its current particle type is used unless you specify another one to be current.
To sketch particles
1. Select an existing particle cloud to add particles to it or have nothing selected to create a new particle cloud for the sketched particles.
2. Choose Create > Particles > Sketch Particles from the Simulate toolbar. This activates a sketch tool similar to the Sketch Curve tool.
3. Draw a stroke in a viewport. When you release the mouse button, the particles are “painted” along the path that you drew.
The particles are drawn using the current particle type you set and the options you set in the default Add Particle property editor.
An Add Particle operator is added under the particle cloud’s for each stroke that you draw.
4. Press Esc to end the sketching mode.
|
If you want to modify the results of the sketching, remember that you can select, delete, and transform the particles in Point mode as you would any object points. |
Editing the Sketched Particles
In the Add Particles property editor, you can edit the sketched particles. An Add Particles operator along with its property editor are created for each stroke that you draw, allowing you to edit each stroke.
To edit the sketched particles
1. Select the sketched particles you want to edit.
2. Open the Add Particles property editor by doing one of the following:
- Click the appropriate Add Particles operator icon in the explorer.
or
- Select any of the sketched particles and press Enter. If you have several strokes associated with one particle cloud, the property editor for each stroke is opened.
3. Set the following parameters in the property editor:
- Multiplicity multiplies the number of added particles. A value of 1 means that one particle is added for every sampling point on the curve you sketched.
- Radius sets how the particles are uniformly distributed within spheres centered at each sampling point on the curve. This parameter controls the radius of those spheres: the larger the radius, the more the particles are spread out.
- Speed is the speed of the particles as determined by the direction and speed at which you drag the Sketch Particles drawing tool.
To see the effect of speed after you’ve sketched the particles, select the sketched particles and choose Create > Particles > From Initial State (see the next section, Simulating the Sketched Particles).
- Spread controls the direction of the velocity. If the spread is set to zero, particles flow exactly along the velocity vector defined by the stroke you make with the Sketch Particles drawing tool. With a value higher than zero, the angle of a cone (in degrees) whose axis is in line with the stroke at that point. The particles’ velocity vector lies within that cone. This is very similar to the Spread on the Emission property page. The spread can be between 0 and 180 degrees.
The Advanced page offers Seed values for the Radius, Seed, and Spread parameters. This allows you to add variation to the value you enter for each of these parameters. See Adding Variation to Particles for more information.
Simulating the Sketched Particles
Sketched particles do not simulate as regular particles, meaning that they do not have velocity or react to forces, obstacles, or events. This is because they do not have a simulation operator. However, you can simulate the animation of a sketched particle cloud.
To simulate sketched particles
• Select the sketched particles and choose Create > Particles > From Initial State.
This creates a new particle cloud (which has a simulation operator as any cloud does) that uses the sketched particle cloud as its initial state. Then the sketched particles have velocity and you can apply forces and obstacles to the new cloud.
For more information, see Creating an Initial State for Particles.
You may want to hide the sketched particle cloud after you generate the simulated cloud so that you don’t have duplicate clouds.
If you added the sketched particles to an existing particle cloud, you won’t see the particles evolve because the particles are added after the simulation has executed at each frame.
To make the new sketched particles a part of the cloud’s simulation
• Select the sketched particles and choose Modify > Particle > Set Initial State.
This bakes the cloud into an initial state so that the sketched particles are included in the simulation.
Autodesk Softimage v.7.5