I know this is probably an easy operation, but I cant seem to figure it out.
Let’s say I have a sphere as my distribution source and a fumefx sim as my velocity field.
When the smoke carries the particles off of the sphere, I want those particles to have their color “baked” in right then and there. So if the texture is animated, it will not effect any particles post-birth. An example of this in action can be found here: youtube.com/watch?v=fpViZkhpPHk
Note how the particle emission is not changing on the particles as they float up… It’s set at the time of their birth.
Actually it is rather easy in Stoke MX 2.3, but it has not been released yet
There, we have a Birth Magma and Per-Step Magma, so all you need to do is evaluate the Color in the Birth Magma (e.g. TexmapEval using the same texture as the emitter’s diffuse map) and it will persist for the duration of the particle’s life.
However, you could work around the lack of Birth Magma in Stoke MX 2.2 and earlier by using the Birth Channel Generator of Krakatoa MX (both commercial and in evaluation mode).
The PRT saved by Stoke 2.2. will not have a Color channel with the desired color value, but you could assign the same material as on the emitter, make sure you have the TextureCoord channel checked if the texture is 2D, and resave using Krakatoa to a new PRT sequence with Color channel saved - this should bake the material diffuse color into the new PRT sequence.
Now use the Birth Channel Generator to create a BirthColor from the Color channel of this new sequence - this will give you a new PRT sequence with a BirthColor channel which will contain the Color of the particle at birth throughout the life of the particle.
You can then copy the BirthColor into Color using a Magma if you need it displayed.
