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About JKeil

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    Justin Keil
  1. Made some progress Did some quick wrangling, trig, and a bit of matrix math. Repurposed some code from a post that I found a while ago. Many thanks f1480187! Still working out some kinks- bend line_upl.hipnc
  2. Hey All, What is the most straightforward way to bend a line (object 1) towards a point (object 2) animating in space. Id like to do this on a point level if possible. I already have a rudimentary setup-but it is not working perfectly. Currently I am using a bend sop, and then simply specifiying the Goal direction as the second object. Fur such a rudimentary approach it works rather well. The problem is it is not 100% accurate. The last point in the line does not always point directly at the point in space. Im getting the sense that if I really want the object to bend towards the point perfectly, I might need to use some matrix rotations on a point level (using a for loop) --but that is beyond my skill at this point. Any suggestions? Thanks! Ive attached a file bend_follow_line_upl.hipnc
  3. Thanks Tomas!-- a much more straightforward method than I was conjuring up. Solved!
  4. Hey, So I have made some progress. I found way to orient the object the way I desired within the loop for work purposes. Working on the setup for transferring the rotations back when the time comes now. now. Let me know if you have any suggestions all! rotation_update_01.hipnc
  5. Hello all, I am sending some geometry pieces back to the origin to do some manipulation. Im using a for loop, and within the loop Ive at least managed to move each piece back to the center. The issue is rotation. I want the objects existing normals "N" to be flush with the x axis while working, and the objects 'up' vector to be flush with Y axis {0,1,0}. I know I can use the arccos(dot(up, up2) function to get the angle I need, (and have done so), my issue is I cant figure out how to rotate the pieces accordingly. So basically--object incorrectly rotated at center-- its existing Normals should face towards +x {1,0,0}, and its "up" vector should face towards {0,1,0}. After work is done, Id like to be able to send the piece back to where it came from, but am a bit stuck. Thanks for the help!!! rotation_reset_at_origin.hipnc
  6. EDIT: I figured out a way to do this: I you generate the group prior to the loop the iterations will merge with each pass .
  7. Hello all, I am trying to grow a selection on a geo group with each loop iteration. I am using a feedback loop rather than a merge each iteration method because I dont want the geo itself to be accumulated, just the values within the groups. Any help with this? If you turn on single pass in the scene file, you can see the point groups I am trying to create on a per loop basis. Id like to have one group or one attribute made up of all these values once the loop iterations are finished, if possible. Ive attached a scene file. Thanks! loop_help.hipnc
  8. Thanks Tomas, I realize now that the workflow wasn't necessarily that clean. The goal was to basically split a geo apart,and then upon reconstruction of the geo, have the all the primitives be exactly the same----no matter what sort of tomfoolery I applied to them. But this now seems like a pointless goal- my setups are working fine without it. Storing the original prim nums in an attribute has been helpful as well. Thanks!
  9. Hey all-- Is there a way to fuse points on a geo without changing the primitive numbers? By default, the facet and fuse both reset the prim values and start them all at one. Ideally, Id actually like to retain the original prim numbers through the operation. Ive attached a file. Thank you! fuse_v001.hipnc
  10. UPDATE-- it seems like there is a fairly easy way around this. All you really need the chops network for is to perform operations on the angle, as opposed to the vectors by the angle. You can then just kick out the angle and apply the quaternion rotation within a wrangle or a vop as you prefer! See new scene file wavyguy_testing3.hipnc
  11. Hey all, Simple goal here, trying to rotate a vector (@N) around another (v@cross) in chops within a wrangle. Im not sure what I am doing wrong. Ideally I would like to import two vectors into the chop network-- @N and v@cross, rotate N by Cross, and then bring the updated N vectors back into sops using a channel sop. I've attached a file. Thanks in advance! Edit: I should point out I am trying to use quaternion rotations I found this thread on the sidefx forums but havent been able to implement the attribute create method as was suggested https://www.sidefx.com/forum/topic/31300/?page=1#post-145135 chops_rot_test_update.hipnc
  12. Texturing Workflow Help

    Ah I see. Best of luck to you! Just to stress again, do check out that first thread for some help!
  13. Texturing Workflow Help

    Kiryha, as to your question, Being completely honest, I personally would approach this with procedural shading rather than a uv approach. Uvs would be too static to look convincing as the tree grows--unless you are trying to animate textures themselves, in which case you might as well be driving this within the shader, and then using masks to 'art direct' the look of the bark along the surface. I am not an expert by any means though so take what I say with a grain of salt. check out this thread. There is a lot of useful info in there on how to approach growth within houdini general. Simon Fielder has great videos on volume trails that can also be used to generate tree like structures procedrually. Try something like that, than start getting crazy with noises and you might get a satisfying result without uvs. Youll notice that the uv based options even within that thread are a bit limited but might work. Hope this helps! here are a few picks of things ive rendering using Simon Fielders approaches Hope this helps! volumetrails_1920X1080_SRGB.tiff particles_01_1920X1080_SRGB.tiff mesh__1920X1080_SRGB.tiff
  14. Texturing Workflow Help

    Thanks for the help Dave. As of now I am trying to work through what you said and come to a solution. Now based on my understanding of what you are saying, I may or may not have a fundamental problem, because at this point my model is built off of the animation itself. I will say that the number of polygons and points on my model even now is NOT changing over time, which seems to be at least half the battle. Might be a bit of overkill but I've attached a series of pictures that show the progression of how the 'character' is being generated so you can critique the workflow if you have the time? It seems to me that I that could follow your suggestion to separate the animation from model in two ways. 1) I could continue as I have been but with a few modifications- I need a rest frame of some kind--similar to a tpose, but perhaps I dont need to build a model first separately to do this? Lets say I have a frame where the character is not animating, the wings are not bent and the curve the body is moving along is flat. This could stand as my rest pose. This could be the point where I lay out my uvs if need (as you say might want to restrict the uv workflow to a nonchanging hero version), but must importantly generate the vertex attributes that should stay the same through the animation regardless of deformation. I just need to make sure this is no recalculation of vertices or uvs over time. Correct? The alternative. A more traditional rig. The model is build in sops, but then the rig itself is built in chops and bound to the character afterwards. Only issue in that case is I would have to learn how to rig traditionally in houdini, which at this point is daunting , but I am not opposed to if need be. Looking forward to hearing back. Thanks!
  15. Hello All, This is a bit of a general advice question so bear with me here. I have a 'creature' I have designed on a point and sop level (see attached--pics as well). It is similar to a sea worm, its entire outer portions are undulating over time. I did the entire animation set up on the point level. To create a single mesh I converted the entire thing into a vdb at the end of the network, smoothed it, and then converted it back to polygons again. Ive attached a base model without the head or tail assets for your perusal. Now I have to set up a shading and texturing workflow, and I was hoping you could point me in the right direction. The art director is going to want to eventually have pretty precise control over the look of the creature so I am not sure procedural shaders are going to be enough. The creature has skin that is changing over time--not drastically, but it is still changing, and the deformation along the edges is enough to make we worry a bit about the uvs. Plus, if I want to make multiple iterations of the creature, animating differently across other curves, Ive essentially negated all the efforts I made in the first place to make this procedural if I do go the UV route for one hero asset! --each vdb to polygon conversion will generate a new mesh every single time I make a change somewhere up above in my network.......... My question is this then, what would you do to texture this creature? I understand this is a bit vague--and there are a lot of variables and questions I havent answered, but just drop of a hat, with a look at the model, would you go with procedural shaders, or does it make more sense to just lay out the UVs on a rest frame, and texture it traditionally? To make this more specific Ill create an arbitrary scenario. Client looks at the creature and requests less undulation, and larger flaps. Easy enough to adjust on the Houdini end if you look at the way I built it. However, this means creature shape changes, and the mesh changes. If the object was textured elsewhere with uvs, we have to redo the textures in Mari. If we could somehow keep the textures in Houdini, this back and forth might be alleviated. Okay, next step, creature gets approved, now they want six of the creatures, each with slightly different coloring and undulation speed, moving along a series of loosely related curves. Easy enough to change the animations and make some subtle changes in shape because Houdini is awesome! But then the texturing and shaders are the elephant in the room again. I hope this is not too vague, but Im just looking for general suggestions not complete solutions as I am a bit new to the shading and texturing in Houdini. Its a bit interesting to me-- I like using Houdini VDbs, but usually because they are used for simulations procedural shaders are the best solution---that MIGHT not be the case here. And if you think I might have to rethink my work flow too that is something I am by no means opposed to either. Looking for a bit of help! Thanks! wavy_littleguy_v002.hipnc