Nebula

The Get->Primitive commands are available in all modules except Tools. They let you define primitive objects which are basic objects with a fixed geometric structure.

For detailed descriptions of polygon mesh objects, curves, and surfaces, as well as the modelling tasks you can perform with them, see the Modelling User's Guide.

The Get->Nebula command lets you create effects such as falling snow, moving dust, exploding text, particles moving from the floor, and composing a face or a text, etc. Each particle is a triangle and the resulting object is a polygon mesh. You can create several models with the same number of particles and then interpolate them with a shape interpolation creating effects like fireworks, swarms, snow, etc.

Procedure

1. Create a reference model to define the boundaries of the nebula.
2. Choose the Get->Nebula command. The Nebula dialogue box is displayed:
3. Select the parameters as desired and click Ok.
4. Click on the Source model.

A new polygon mesh model is created with the specified number of triangles.

Parameters

Particles

The number of particles you want to create.

Seed

Determines how the random number generator is initialized. If you create two Nebula effects with the same seed, the simulations are always the same (that is, they use the same random numbers to calculate the effect). With different seeds, the random number changes, producing slightly different effects. You can use any number from 1 to 100 as a random seed.

Size

Describes the size of each particle in SOFTIMAGE units.

Particle Positioning

Describes where you want to place the particles.

• Bounding Sphere: the particles are dispersed from the surface of the Bounding Sphere of the selected model.
• Thickness describes the thickness of the Bounding Sphere.
• Bounding Box: the particles are dispersed from the surface of the bounding box of the selected model.
• Volume: the particles are dispersed into the volume of the selected polygon mesh. Raytracing is involved in this option, so this is the slowest mode.
• Vertices: the particles are dispersed on the vertices of the model if polygon mesh, on the control points if patch or curve, or on the null itself if a null.
• Edges: if the model is a polygon mesh, the particles lie along the edges of the selected model.
• Polygons: if the model is a polygon mesh, the particles lie over the polygons, which must be convex.

Jitter

The particles are randomly shifted (based on Seed) into a sphere of Radius.

Copy Model Rotations, Scaling, and Translations

The new polygon mesh inherits the selected transformation (rotation, scaling, or translation) of the selected model.

Compute Normals

Compute the normal values on the resulting polygon mesh.

Material

• Random: The number specified in the Materials text box is created randomly and each particle takes one.
• Copy from model: Each particle takes the same colour as its polygon; otherwise, the first colour of the model is assumed.

Last updated 02-apr-1998