give what shader to fire particles?

[musickent]

i learned how to create fire using particles. but dont know what to how to apply shader to particles before rendering... without right shader, all particles are grey spheres when rendering...

i cannot fine tutorials about applying shader to particles. in HOudini 4's demo, they all used materials, but i cannot see what to do in Houdini 5 or 6.. i think this is a seam when houdini using SHOP instead of materails.

plz give me a hand.

thanks in advance.

[cs00bren]

i think with out looking thiers a fire shader in the vex section so create a vex shader and plug the fir ematerial in to the out put!??!?!??!.

that could work very unlikely but if it does

bren.

[musickent]

i tried that, but the fire rendered out is weird...ugly!! i don't know what else should do.

[old school]

The fire VOP is just for 2d fire. It should look OK if applied to a NURBs grid facing you.

Here is a start at a fire VOP shader in Houdini6. Sorry if you are using H5, maybe it will load with some complaints.

It uses the same technique as the old shaders did by denting spheres with noise. It is based on the smoke VOP but with an absolute VOP after the pnoise VOP to get the sharp noise.

Animate the time parm in SHOPs with $T (time in seconds) to get movement in the noise/smoke for a nice realistic effect. Be careful with the other parms. Touchy this shader is, especially with the Alpha Roll!

vop_fire.hip.zip

[musickent]

thank you so much. i will study it carefully.

thank you again!

[musickent]

old school, what is the sop "attributecreate_life" for?

could you explain a little bit.

thanks

[old school]

The "life" attribute out of POPs and the particle SOP is a two component attribute. Parameter VOPs can't pick this up as an import variable.

You have to create a new "life" attribute as a vector with three elements and use $LIFE1 and $LIFE2 for the first and second elements of the new life attribute. The two have the same name but subsequent references to $LIFE will access your newly created LIFE attribute since it now has a correct signature added by the attribute SOP.

This part of the attribute Houdini workflow still needs some work to make it squeaky-clean, but what the hey, this works.

My only concern is that you just created another attribute on the data. If the geometry was huge, you just added more to it!

The whole idea of this is to defer the attribute generation well in to the renderer a.k.a. the shader. You see with LIFE accessed in the shader, you can color the particles there. Generating Cd in POPs is slow for playback and like I said above, every attribute you don't need, toss it because it just takes up memory. A critical thing if you have 100,000+ particles.

[musickent]

hard for me... i am working on it still.

thanks for your help