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rtep last won the day on July 2 2015

rtep had the most liked content!

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About rtep

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    Chicago, Il

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  1. Need help on Tornado simulation

    Here's a slightly different set up that I found worked well to keep the smoke moving. I modified your set up, it's not perfect but it will show the workflow. You scatter points in the bounds of the tornado, transfer your rotation vel to the points and bring them into the dop as a gasparticlefield. Tornado_test7_rtep.hiplc
  2. When you merge objects together all of the merged objects will share one detail value. One solution is to merge your objects together, create your attribute as a point, then split your objects into there respective chains and use an attributepromote to promote that point attr to a detail.
  3. wobbling particles around animated curve

    If you make a pop network there is a popcurveforce node that can do exactly that. Use your curve to emit particles and then use that same curve in the popcurveforce with the orbit value turned up. It is a relatively straight forward node, so if you play with the values you should be able to figure it out.
  4. If the geo isn't animating make sure to put down a timeshift and hold a single frame. Sometimes if you're using an alembic or you have certain nodes houdini will recook the vdb even though there's no change to the geo.
  5. You're probably right, all I know about it is what I saw in the tutorial. What you said about not being able to use variables in {} is probably more important anyway.
  6. https://vimeo.com/67677051 It's also discussed in Ari Danesh's tutorial (starting at 19:30). He says set() is much more effecient than {} to calculate.
  7. Velocity field from animated geometry

    Howdy, I can take a look at the files tomorrow but sadhu might have you covered. But I'll jump in and answer your other questions quickly. The volume won't be visible when the velocities are negative but they are still there. The volume, by default, will only display positive values. I'm not sure if there's a node or parameter directly used for feathering but as far as controlling your velocity volume there are 2 important things to remember, the resolution of the volume and the amount of points that are being sampled. The resolution of the volume node will define how fine your vel field is. By increasing the voxels you will get more samples of vel data and the particle motion will match closer to the animating geo, which will become more apparent with deforming geo. Resolution works in tandum with the number of points you are sampling the vel attr from. A higher res volume won't do much without more points to sample vel from. So you can scatter points in your geo or scatter points on the surface of the geo, get your vel attr and then use a vop to add noise to the vel or feather the field based on distance from an sdf of the animated geo... it's pretty limitless once you get it going.
  8. Velocity field from animated geometry

    Here's one way to build a vel volume from a trail. You can then use the vel volume in an advect by volume node in your dop pop. Check it out. This might be enough for your project. vel field from points_v001.hip I find you get a better result if you create a big container of smoke and let your vel volume disturb that. Have your points floating in the big container and they will be affected by the disturbance of the big object. But that's a little more involved and this file will be simpler to understand and hopefully get you going in the right direction. Let me know if it helps.
  9. Color Won't Move Object?

    hi, You have to promote CD to a detail in this instance because a transform node doesn't work per point, it is per object. A single transform node can't move half of the points one direction and the other half another direction, it's all or nothing. So you have to call a single value attribute, like a detail attr. You could also use the point expression in the transform to call a single points color value, or centroid expression for pivot. If you want individual points to move in different ways you need to use a different approach like a wrangle or a vop.
  10. Glue Wire to Animation - no rotation!

    I think the issue you're seeing is that the twig isn't picking up the parented transform data. I took your final twig and object merged it into another object and sent that one to dops and it seems to work. It's odd because you do have use object transform enabled? RND_GrassTwigs_newGeo_v01.hip Maybe someone else sees something I don't? Another tip in case you don't know is that you can add a point float attribute called pintoanimation to your twig. Set the value of that to 1 on whatever points you want to stick to the anim. Then you don't need the pin constraint. You can try it by enabling the group node and attribute create node I put in the twig object and then display the dop net after the rbd and wire merge.
  11. That's the one mestela! Nice work. I spent all of yesterday trying to rotate a bunch of feathers along their own axises and the makeinstancetransform node in your setup ended up being exactly what I needed. I always struggle to build the rot data I need in vops.
  12. I'm not sure which thread this file came from but it might help you. It's a different method. I haven't looked too closely at it but it seems to be per prim rotation without a sim. Might be good? Per_prim_rot_vex.hipnc
  13. Howdy Ryan, did you ever get the initial orientation working?
  14. and yeah, you can disconnect the resize node if you need to.
  15. pyro_with_centroid_exp.hip see if you can get it from this setup. If you have issues let me know and I'll grab your file.