Texture Based Emission

[Solitude]

I'm wondering how to emit pyro/liquid from an object with a map applied to it, where the intensity of the map controls the amount fire/smoke emission. ...From there I could use the same technique to control any other piece of data, but I just don't have any idea where to start. I think I could figure it out with point colors, but I would like this to use uv coordinates instead (ie: not point attributes), and that's where I get lost. ..Vops?

Second Question: How would this same thing be accomplished with particles?

...I was going to ask about how to turn particles into voxels / transfer data, but I was just remember that Peter Claes covers that in his thesis paper...

Thx!

[dynamoanders]

Oooh. I wonder too how to do this.

If anyone has an answer or suggestion, please post it here.

Thanks

//Anders

[phong]

I'm curious about the answer for question 1, too!

But I can answer question 2. It's quite easy. You create your geometry and assign your UVs to it so that your texture maps well to the surface. Then you use a VOPSOP and fetch the UV attributes with a vector parameter node and use these for your colormap which you can use to load in your custom emission map. Convert the output of that map to a float value which you pipe into a float parameter node (make sure export is turned on) and name that parameter properly, i.e. area or emission. After the VOPSOP you promote the attribute as primitive and within the Source POP of the POP network you can use emission by surface (attribute) which should point to the parameter name of your exported emission parameter. And that's it!

Phong

[Solitude]

Awesome, thanks phong -- I figured out some of this stuff, but using "emission by surface (attribute)" sounds way better than what i was doing.

[phong]

You could also use the pic() function in your birth probability which gives more accurate results, but this function is insanely sloooow.

[Pazuzu]

I want to share my approach for emitting fluid from a sequence of textures.

To control the emission with the textures values, you can then transfer the point color to the fog volume with a volume vop.

Fluid_ImageSource.rar

Edited April 6, 2010 by Pazuzu

[Pazuzu]

Here is the example with the values from the texture to control the density.

PS: I found that is better to work in this case with a volume sop, because it don't need to rebuild the volume every frame, is more fast in this special case than isooffset sop.

Fluid_ImageSource.hipnc

Edited April 6, 2010 by Pazuzu

[Solitude]

Here is the example with the values from the texture to control the density.

PS: I found that is better to work in this case with a volume sop, because it don't need to rebuild the volume every frame, is more fast in this special case than isooffset sop.

Thanks for the tips / examples, they're super useful!