ejr32123

I do not have much experience with hair other than using xgen for a bit and watching tutorials/demos of other software like ornatrix. I recently spent a lot of time learning hair in houdini and I was wondering if other people had a similar experience. Sops vs OBJ. I hate working at obj level with hair nodes (or in general). You have to keep diving back and forth to different objects to access data, and it's really frustrating and painfully slow. So I switched to mainly using sops. However, things were really strange there too. The first thing I noticed is that none of the radial menus work. Since you can’t really freeze hair (so they won’t be affected by the brush) you can select hair then use the radial menu to get back to the brush and only brush those selected hairs. However, that doesn’t work in sops because the radial menu and most of the shelf tools only seem to work at obj level. To brush only selected hairs, you have to click the guide groom node, click the selection arrow, select the hairs you want, then hit enter, then manually switch to the brush tool. That is just way too slow. Then, if you change the amount of hairs, your selection breaks and the hair does weird things. Changing the amount of hair going into a brush node generally works fine because it interpolates, unless you made selections in the process (which is what I have been doing). Some things just don’t make sense or are slow. The tools were clearly designed to work at obj level, even though you can access them in sops. 1. Manually placing guides at sop level. I turn on shade open curves so I can see the hair width when working at sop level. When you use the guide brush tool to place guides, the guides immediately disappear. I found out that working in sops, the guide groom plant guide tool does not allow you to create a width attribute. This means the width gets assigned a value of 0 and thus disappears because you need a width attribute. The way I fix it is to unlock the digital asset and manually add the attribute. See video 2. Changing the length of the hair does not resample the width along length. This literally makes 0 sense. If I use the guide brush to lengthen tapered hair, it seems to not really get longer. However, when I rendered it my hair was much longer than the viewport. Then I learned that it's because width was not resampled to match the new length, so 60% of the hair was invisible in the viewport. To fix it, I add a resample to add a curveu attribute, then I resample the width along curveu. See video 3. Some brushes are insanely slow. The smooth brush is the slowest of them all, you can only brush a few hairs before it gets too slow to use. 4. The brushes in general just don’t seem to work well compared to other software I have seen. They are generally slower and harder to use/give you worse results. 5. The clumping can give you different results based on your uvs, and if you update the uvs the clump node doesn’t always update correctly. I have to delete the clump node then hit undo to get it to update, or restart houdini. 6. Recaching. This is so annoying. If you work in sops, the recache menu button doesn’t work so you have to manually select all the guide grooms and hit recache. I also noticed in sops that I have to do this when I load my project, otherwise I get shown incorrect results. When working at obj this was not an issue. I don’t want this to be all negative so I will say this: The parts that are procedural, the guide process nodes are amazing. The guide advect tool is amazing too. You can get very good results without ever touching a brush-this is the great part. Does anyone else have any thoughts on how grooming compares to other softwares? To reiterate, I just found manual grooming with brushes to be really slow and painful, with a lot of manual setup or switching between obj nodes.

seemed to fix it by adding a fbik configure joints and limiting rotation to x axis

update: I figured out the 2nd part, how to orient the rotation. As I said earlier, I used two stabilize joints, one to stop sliding, and one to fix the orientation. All that going into an ik solver. hip file included (its not prefect, but you get the idea). I still need help with the first part though. odforce.zip

edit: I figured out how to lock the foot, I used two different stabilize joints: one to keep the the foot from slipping, and one to match the rotation on the foot to the floor. I did that inside to an ik chain to update the rest of the leg hip is below on next post. Hello, A few questions about cleaning up a mocap clip from mixamo when applied to this mech character. I could not include the whole mech, but the l eg is included in the hip. If you play the clip, you see unrealistic motion because I need all the joints under the left upper leg joint to stay in the same position in x. You can see how it bends my mechanical leg outward to the left, which is no good. Basically, what ever x axis position the upper left leg joint is at, everything below it must be at the same x position. The bottom rig is the rest pose, whats circled is the way it should look. All the joints in the same x position. odforce.zip Final question is how to keep the foot resting on the ground. Is that joint stabilize? I just want the foot to lay flat while its on the ground. Thanks!

Hello, In (xgen) maya you can select tubes and create guide curves based off the initial tubes selected, given that your tubes are open and have uvs with the 0 toward the root (next to scalp). How can I recreate this setup in houdini? I found this tutorial here https://youtu.be/CqdMxq4N-uo but that method only seems to work (the part where he generates the beard from tubes) if you create the tubes in houdini, because his method uses uv's that were generated from the curves that the tubes are from, so the uv's are perfectly laid out for the tube spanning 0-1 in a square. My tubes are from the modeler and are messy and have no uvs. Any ideas on how xgen does it under the hood or any other way in houdini? Thanks

ill look at bifrost

Hey, Was wondering if anyone could offer any insight on using houdini to generate/simulate hair in a maya pipeline. One method I could use xgen to generate the hair and sim the guides in houdini then bring that back into maya. But then......I would have to use maya and xgen, which I really don't like. Since we are using redshift I know I could export the hair as a RS and bring it into maya. But then if we want to change the hair width, make it slightly longer, etc the other maya artists would not have that control it would require me to change the settings in houdini and export. Can anyone offer some knowledge on a work flow creating hair in houdini and bringing it into maya? Also side note, importing curve abc files from houdini into maya seems really inefficient. The way it imports into maya is quite strange, like a new shape for each curve or something weird like that. Thanks

thanks, Ill update if I get anything working. why not use kinefx? Its just rigid parts with no capture I don't really need procedural rig. From what I have seen, actually animating in kinefx isn't completely finished if I am not mistaken.

Are you saying you want fire then smoke? I cannot tell, but it looks like you are emitting density. Have you tried just emitting heat/temperature and using combustion then using emit smoke? That will cause the sim to start as fire then emit smoke.

Hello, I am new to rigging in houdini (or just in general). While I am waiting for a more full featured version of kinefx figured I would mess around in obj rigging. I set up a basic IK with twist affector to control a sort of robotic arm. I needed to limit which axes the different bones could rotate on as shown in the photo. However, the IK seemed to ignore the angle range I set. Then I read that you need to use ik with constraints to get that working. So I enabled that option which led to these problems: 1. Once you enable ik with constraints, you know longer have that twist affector. So how do you control that area if you can't use a twist affector? 2. When I move around my arm, the middle joint snaps around chaotically, unlike when my twist affector was on. Is ik even the way to go for something like this? https://gfycat.com/parchedglasscatbird arm.hiplc

oh duh!! thanks!! lol I over looked that

I reported it as a bug, the response was: "It should work properly if you set the substeps in the vellum solver down to 1. If you need to increase the substeps, please do so in the top dopnet node. This will ensure that both constraints and velocity are in the same substep." So I guess its not a bug then. Still seems weird to me.

thanks!

hello! I encountered this strange problem, possibly a glitch. I have a very simple scene with a line that has a vellum string constraint attached to it. I added some point velocity to add motion. For some reason when I change the substeps on the vellum solver it ignores the incoming value. In fact, some substep values even make it go the opposite direction, some values don't move at all. You can see in my video when I change the substeps on the dopnet it remains fine. Am I doing something wrong? thanks eidt: I forgot to mention it does the same thing if I emit vellum from points and and tell it to copy the v attribute from the instance points. vellum.hiplc

Hello, Been playing around with the pop fluids. I can get some nice looking results with fairly low resolution. Of course it doesn't mesh very well with few particles, so I turn up the resolution but there are just way too many tendrils and drops. Look at my two photo before and after making the pop fluid a higher res sim. I tried almost every setting and nothing seemed to help. It would be nice if there was a scale setting or something. Any ideas? thanks