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Technical Discussion » primitive groups and packed prims
- Midasssilver
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Fixed. The problem was that you were transferring groups in your assemble, which isn't necessary.
Technical Discussion » Mantra Shadow Pass in Houdini 17.5?
- Midasssilver
- 310 posts
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You need to write out the image plane as an exr, and with the shadow matte shader, you should have white shadows. Then the black part becomes transparent with the exr, and the white becomes your shadows. Then you invert it, and comp it in.
Technical Discussion » recomendations on wire object settings to simulate a rope
- Midasssilver
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Post a hip with your best try, and someone (maybe me) will improve it for you. I'd say, you are mostly likely having an issue working with the number of points you are using, but I'd need your scene to see.
Technical Discussion » How to emit smoke from fractured object?
- Midasssilver
- 310 posts
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Skip the debris for now, and just emit smoke from your main rbd simulation. After you cache out your rbd sim, it should just be geometry. If it is still packed, unpack it. Then, at obj level, with the node that contains your rbd selected, ctrl+click the source from surface button, and you will get smoke coming from your pieces. Then, you just need to isolate the pieces according to their velocity, to get smoke from the right pieces at the right time.
Technical Discussion » Volumes not displaying correctly
- Midasssilver
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Technical Discussion » Convert bgeo file to vdb?
- Midasssilver
- 310 posts
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You can drop down a convert node, and convert from your obj type to vdb. You just need to choose what the original type is in the “convert from” field.
Technical Discussion » Particle activity
- Midasssilver
- 310 posts
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Probably want to start with something like a particle sim with low velocity in a specific direction (X probably), and a little noise in Y and X. Then have them interact with either a static deforming collision object, or bring in an external velocity force to move the dust.
Technical Discussion » Prevent fur stuck inside the skin
- Midasssilver
- 310 posts
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Technical Discussion » Houdini Zero Gravity Simulation
- Midasssilver
- 310 posts
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Technical Discussion » Vellum collision - what am I doing wrong?
- Midasssilver
- 310 posts
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The main issue you needed to fix was increasing the substeps and constraint iterations until the pops you saw went away. If you checked your scene, you could see that you were getting collisions, they just weren't accurate enough with the interpenetration you were getting. This was also due to how high res your cloth was. So, you had to increase the substeps and constraint iterations high enough to resolve that number of points. Uploaded the fix.
Technical Discussion » VoronoiFracture with complex geometry
- Midasssilver
- 310 posts
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Most likely because you are using a rigid body solver with RBD packed object, instead of a Bullet Solver, but post a hip and Ill check it out.
Technical Discussion » Houdini Zero Gravity Simulation
- Midasssilver
- 310 posts
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Bump. It's possible to bind the position to a point in sops, but what you are looking for seems more difficult. It's kind of like just giving the RBD object an inherited velocity, because if the fan force is kept in the same place on the same object, and there are no rotations or collisions to get in the way, then it will just keep moving continuously in the same direction.
I was interested in seeing how someone would approach what you are trying to do as well.
I was interested in seeing how someone would approach what you are trying to do as well.
Technical Discussion » Hair
- Midasssilver
- 310 posts
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You are biting off a lot with your current task, especially for a school project. I'm not sure how you are converting your hair to guides in maya, but we used xgen to create them and give us separate descriptions for each section of hair. Then we simmed the curves we created in maya, in houdini, the exported them out as an abc. When we brought them back in, provided the descriptions were preserved, we could link them up in xgen and generate hair from the simulated curves there.
While this doesn't account for curves that are made in Houdini, it is a workflow that I know does work, if you are using xgen with maya.
While this doesn't account for curves that are made in Houdini, it is a workflow that I know does work, if you are using xgen with maya.
Technical Discussion » Flip Sim merging with Ocean
- Midasssilver
- 310 posts
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Also, I should not, it is often suggested that the border that you find there could more easily be corrected in comp. That might be your safest bet, if you can't get the parameters I suggested working well.
Technical Discussion » Import Alembic - Unpack and Convert not working
- Midasssilver
- 310 posts
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Look at the collision volume representation in your dopnet. There is a blue representation of what your collision volume looks like that is dependent on the division size of your collision object. That will tell you the quality of your collision volume. If that doesn't look clean, you won't get proper collisions.
Technical Discussion » Pyro H17 - particle sim source / smoke loses momentum
- Midasssilver
- 310 posts
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I don't think there is anything wrong with your setup. You are getting velocity while there are particles, and when there are no more particles, there is no more velocity being sourced, just as there is no more density being sourced. The smoke definitely gains momentum from the initial velocity burst, because if you disable your gravity and drag, you will see that it continues moving in its initial direction, just with a loss in velocity over time. I'd probably need to see the tutorial you are mentioning to see what he did differently. Perhaps something as simple as reducing the timescale so that velocity is lost slower might do the job. It does feel like everything is working as intended though.
I made some tweaks to your file to show you what happens when you increase the source velocity, and tweak how your velocity is being sourced a bit. Here, you can see the velocity die off over time, as opposed to just disappearing when your source disappears at 1018. Here, you can see a more gradual loss of velocity, which makes sense as velocity is only sourced as the points that are sourcing it exist.
I made some tweaks to your file to show you what happens when you increase the source velocity, and tweak how your velocity is being sourced a bit. Here, you can see the velocity die off over time, as opposed to just disappearing when your source disappears at 1018. Here, you can see a more gradual loss of velocity, which makes sense as velocity is only sourced as the points that are sourcing it exist.
Edited by Midasssilver - Aug. 22, 2019 14:24:23
Technical Discussion » Export Houdini Groom ( curves/guides ) to Maya
- Midasssilver
- 310 posts
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With our workflow, we initially export the curves out of maya with the proper names for each section of the hair(descriptions). Then we bring them into Houdini, attach them, sim them, then export the curves out as an abc. Then, back in maya, we use those curves to instance hair onto each one using xgen.
Technical Discussion » Getting Motion blur on volumes in Redshift. Need to split vel to vel.x, vel.y, vel.z. How?
- Midasssilver
- 310 posts
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Technical Discussion » RBD
- Midasssilver
- 310 posts
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You basically need to separate your object into the individual parts using a blast or delete node and delete by groups or attributes, depending on what the object is separated by. Then you need to visually identify which objects are closed, they won't fracture right if they aren't closed. Then you need to use a polycap and polybridge to close those surfaces. All of this might be biting off a lot more than you can chew though.
Technical Discussion » Pyro H17 - particle sim source / smoke loses momentum
- Midasssilver
- 310 posts
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Post a hip file and Ill check it out. That'll be the best way for me to diagnose this. If you can't share the file for whatever reason, then try and replicate the problem in a simple file you can share.
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