Extend your popwrangle code to examine the @hitnum attribute as well. Store the time in a new attribute. Time is in seconds, so you'll have to convert it to a frame based upon your current FPS. Something like... if(@hitnum==1){f@first_hittime=@hittime;}

I think your assumption is right. It looks like it is a divisor deciding whether or not to reseed on a any given frame. If you set it to 5, the reseed will only happen every 5 frames is my guess.

If you're just doing vines across a body, you might want to use the ray node to project the underlying curves onto the body, then generate the mesh along those conformed curves. This approach might preserve the volume of the mesh a little better as well.

Maybe check out this link.

This one still seems to work in H19.5.

I worked through the meteor shower tutorial today. The tutorial used Mantra rendering, but I set this HIP file up for OpenGL and Karma output. OpenGL on the left and Karma on the right: ap_tut_meteor_shower_111622.hiplc

Check out the help card on the vellum source node. You can change the emission type to every frame then control activation via modulus just like RBD.

There are a couple of things you can try. In the houdini.env file bump up the max texture resolution. KARMA_XPU_MAX_TEXTURE_RES = "4096" On the Image Output/AOVs (Render Vars) tab set the Pixel Filter Size to zero. I have experienced improvements with these settings, but Karma doesn't give you a 1:1 crispness compared to the original texture.

I installed the two wrangle, and I'm getting some action, but it doesn't really look like my supplied heart shape. Can you recommend any settings for the two wrangles? ap_lib_infinite_knot.hiplc

One parameter you can play with, which drastically reduces the initial mushrooming effect, is Cooling Rate. Try setting it to 1.0. ap_smoke_steam_whistle.hiplc

Some render systems default to what is called "headlight" lighting if no lights are detected in the scene. You may have to turn that off on your render system to achieve total darkness. I do this if I know I am lighting my scene exclusively through emissive materials. Another work around is to drop a light in the scene and set the intensity and exposure to zero. As long as any light is in the scene, the headlight won't be generated.

You may need to use the @instancefile attribute to reference geometry on disk, rather than @instancepath.

You might not to simulate that at all? Just create a volume from a cone, add noise to the density, and animate the offset of the noise?

That looks like a bug in the hair node. Try simulating your lines as cloth instead. You can add a shape match as well.

I played around with adding this to SOP based billowy smoke. When the density reaches the bright area/height of the control field, the gas disturbance takes place. ap_sop_sparse_control_field_gas_disturbance.hiplc