Prepare to use the Fire effect

Before you use the Fire effect, be aware of these issues:

• Use the Fire effect on only one object at a time.

  To apply Fire to a group of NURBS surfaces, first convert each surface to polygons and combine the surfaces. From the Surfaces menu set, select Modify > Convert > NURBS to Polygons, then from the Polygons menu set choose Mesh > Combine.

  To apply Fire to a group of polygonal surfaces, simply combine the surfaces with Mesh > Combine.

• If you emit from a NURBS or polygonal object, the size and shape of the object affects the quality of the fire. You’ll need to use an object large enough to generate an adequate flame area. If you emit fire from a curve, avoid using a curve with abrupt changes in direction.
• It’s often useful to use the Fire effect on the same geometry more than once. By setting options differently with each usage, you can create a complex look not possible with a single usage.
• If you want to animate the movement of the fire around the workspace, consider using the Fire effect on a particle object. You can work with per particle expressions on particle objects, so you have more flexibility in altering the fire’s motion.
• You’ll often need to emit flames from part of an object rather than from its entire geometry. In some instances, the part of the object where you want the fire won’t have geometry present. A common technique in such cases is to emit from an invisible geometric object in that area.

To use the Fire effect

1. Do one of the following:
   • Select the object or CVs, edit points, vertices, or particles that you want to emit fire.
   • To create a positional emitter, deselect all objects.
2. Select Effects > Create Fire > .
3. Set attributes in the Create Fire Effect Options window (see Edit attributes of the Fire effect) and click Create.

   The Fire effect creates an emitter, emitted particle object, expressions, ramps, textures, and several fields.

4. Play the animation.

   Emitted particles appear as circles in the workspace because the particles are displayed as the Cloud render type.

   Here’s an example with Shading > Smooth Shade All turned on.

   

5. Add a light to the scene and software render to see the fire.

   From the Rendering menu set, for example, select Render > Render Current Frame.

   

Edit attributes of the Fire effect

The following pages explain attributes you can set to tune the Fire effect. The Fire effect creates several custom attributes in the emitted particle object it creates. The custom attributes control a combination of field or emitter attributes to lessen the settings you would otherwise need to make to tune the fire.

Tune the fire’s appearance

• Adjust any other attributes that are controlled by expressions, ramps, and textures to tune the effect. To learn which expressions, ramps, and textures are created by the Fire effect, apply Fire to an object in an otherwise empty scene. Use the Attribute Editor, Expression Editor, and Hypershade to see the additions.
• Edit attributes of the Cloud particle render type.
• Turn off the turbulence field by disconnecting it using the Dynamics Relationship Editor.
• Animate the emitter to move the fire in your scene.