Category: hou-effects

Archived post by jim.meston

Can easily replicate a single source emitter.

“`cpp int trigger = int(rint(rand(@piece_id)*215));
if(@Frame<trigger){ @P = v@P_orig; @P.x = (noise(@Time*.4)-0.5)*8; // or just tracking an object pos v@v = {0, 1, 0}; }
if(@Frame>trigger){ @pscale += 15; @pscale = clamp(@pscale, 1, 100); } “`

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Archived post by lewis.taylor.

yeah

so normally I will set my density to the highest fidelity I need, and unless there is some insanely detailed velocity requirement will up the Vel scale

@hanhanxue VDB point advect will still suffer from not being able to 100% push them into the smaller eddies, so I think it’s best to just own it all in the pyro sim. I took Matt’s file and just added these vortex nodes. It’s a bit heavy handed here, but vortex confinement and vortex boost along with nice substeps will give you control to make these swirls. You can click the initialize option on the SOP pyro to drop down a volumes sharpen setup. This will sharpen density _just_ a bit more, saving you some precious sim time.

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Archived post by lwwwwwws

shit i have done to help fill in gaps between points like that: – copy the points a few times and offset each copy a different random amount along v if a pop sim, or if it’s procedural distortion keep N up to date through the distortion and move them at right angles to it to avoid making the shapes fluffier – transform to NDC, flatten in Z and calculate density by finding average distance of closest 10 points or whatever so you have a screen-space measure of how “piled up” the points are getting and can avoid adding too many in dense areas – render velocity or screen space tangent vector AOVs, dilate or infill them in comp, then vector motion blur which will follow the shapes and avoid blurring across them – vector blur in comp just based on image gradient – should be easy in cops now to do slope blur which blurs along contours instead of across, usually makes things look “silky”… it’s what you do for hair retouching in shampoo ads

Archived post by lewis.taylor.

it can be sped up

regarding creating density, here’s a little trick I use with all my sourcing. It makes the emission more natural, and reduces having bad looking sourcing visible.

mult your density with a remapped normalized age. This starts it out from zero, ramps up, and fades down

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