Jump to content

jim c

  • Content count

  • Donations

    0.00 CAD 
  • Joined

  • Last visited

  • Days Won


Everything posted by jim c

  1. I'm trying to figure out how to resume a render from hbatch using H 15.5. Let's say I have a mantra node named "mantra1", and I've got "Resume from Checkpoint files" turned on, and the frame range is set from 1 to 100. If I open this in hbatch, and do this: render -V /out/mantra1 then let it go for the first 20 frames and hit Ctrl+C to stop it. I can see a checkpoint file is created, at the right frame number. However if I load it up in hbatch again and render, it starts from the beginning. Is there something I'm missing? Or is this functionality not working in H 15.5?
  2. Simply Awesome! Thanks for posting this, there's all sorts of great ideas/techniques in there to work with!
  3. WIP - ok++'s softbodies RnD + .hip files

    Agreed! I haven't had a chance to look, but the videos look really cool! Thanks for sharing.
  4. I've got a sky rig that I would like to cache to disk. But when I use a FileCache SOP at the end of the network, cache it, and then turn of the Load From File toggle, nothing comes back. Are there other steps I need to take to get this to work? sky-nocache.hipnc
  5. VDB Combine

    Use a timeshift SOP and set it to frame 1?
  6. I have a faerie creature which in real world units is quite small, maybe smaller than the palm of your hand. The original model is modeled in the scale of a normal person, so about 172 cm tall. I've got the model in this scale rigged up and ready to go. So the question is how to bring it into the scene. Does it make sense to scale up the actual scene so that it everything is scaled up relative to the character and then animate that, and then scale it all back down, including the animated character, after the animation is done? The reason for doing this is that I want to get the feeling of size right, so I presume I need to render in real world units. Is this the best approach or is there a better way to do this?
  7. Hair FX in Houdini

    Thanks for doing this, the video looks like it covers all sorts of really cool techniques. Can't say how nice this is to see.
  8. I've got this growing tree model, and I wanted to animate the growth sequence starting where it pushes through the dirt. Using the GrainSource SOP and the PopGrains DOP I can get some decent results, so I now have some clumpy particles. Once I have those what's the best approach to rendering them? Would it make sense to use them as the source for a voronoi fracture sop and have the particles drive the various pieces? Or is there a better approach?
  9. I've got a nice little lsystem that is producing a tree. The goal is to animate this process. So I'm going from this to this over around 360 steps. So far so good. The only real problem I'm having is how to best generate UVs while it's "growing". To add nice detailing to the geo I use the UV data to apply some deforms. My problem has been that to get this to work nicely I hand built the UV map in Modo using the last frame of the tree's geo like so: Then I used the UVLayout SOP to layout all the islands horizontally along U, and then gradually increased the V values as they run along the new U coord the to "twist" the UV, which then makes it easier to deform it to this: I don't need to do this to all the geo, just the lower trunk portions, the higher branches don't matter they'll be hidden by all the leaves anyways. So, the question is, how to apply UVs like this for the rest of the previous intermediate frames? I've tried to use a wire deformer to get the final geo into a similar position as the growing geo and then use an attribute transfer SOP for the UVs, but that doesn't work so well. Another idea I had was to use a foreach block to isolate the individual branch pieces and then somehow regenerate uvs for each piece, but while I can get the foreach to work I haven;t figured how to re-apply the UVs. The geo us being created with PolyWire Sop which I think I need to stick with as it gives the best results at joining everything together. I've cached out various pieces, so I have access to the underlying lsystem wires (prior to it being fed to the PolyWire sop) if that helps. Any ideas would be most appreciated! Thanks
  10. And here's the result now, a couple of captures of different frames
  11. OK so I more or less figure out how to get this to work. First problem was that when I switched to the UV viewport, the UV's didn't show up so it was difficult to tell what was going on (they were there however, I could export the model and see the uvs in Modo). Next step was to delete all the branch geo as it was being created. Using a delete Sop with an expression that checked against the gen attribute (that's supplied by the Lsystem) pretty much did that. Next I used the UVLayout Sop to layout out the various UV islands that the PolyWire SOP creates more or less horizontally. This is done with UV at the vertex level NOT at the point level. After this was done I used an attr promote sop to calc the max UV value and store in a detail attr. Created a Attr Wrangle Sop to adjust the uv.y value so its gradually increasing as a function of uv.x/maxuv.x value. At this point we've got twisting UVs, not matter what frame we're on! The rest was re-suing the existing technique I'd worked out for the static hand built uv's I'd made in Modo. It's not perfect, when you promote the vertices UVs to point UVs there's some distortion that happens at certain areas, but I can live with that, maybe some clever camera angles to avoid focusing on those spots.
  12. Knife always perpendicular to grid

    if the grid is flat, then you could use the normal() expression, pass in the grid's path, pick any prim, 0 should be fine, and then use that in the Knife SOP's direction parameter.
  13. Couple of things you can do. Look up "Box Modeling" and you'll see how a simple box can be divided up and manipulated into more complex forms, like a head. To start with that drop down a Box SOP. You can then go to the Polygon shelf and use the cut lines or edges (I can't recall exactly what it's called), but it lets you interactively place new edge loops in your geo. That lets you add more detail to the mesh, where you want it and form there you can use the edit sop (typically in Point mode) to manipulate (transform/rotate/scale) points. If you just model one side, along the x-axis for example, then you can delete the other side, and use the Mirror SOP to mirror over your geo. You can use a series of metaballs all merged together and fed into a VDB Volume and then converted into a mesh (Convert VDB SOP) as another way to set up some core forms, and then use the retopo tools to give proper edge loops. There's the NURBs tools as well, but those are probably more hassle then they are worth.
  14. Thanks, I wasn't thinking along those line, it's a project for my wife, she wanted a magic growing tree Unfortunately it's taken forever to get done. Id be happty to write up the basics of how it works though (most of the core is coming up with some nice L-system code).
  15. I have a chunk of geometry, lets say a tube, that's off in space, and it's been rotated around. I'd like to "normalize" it, to translate it to the origin, and then rotate it such that's point straight up in the Y axis, perform some operations on it, and then put it back in it's original position and orientation. I know how to normalize the translation, but I'm stuck with the rotation stuff. Is there a sop that does this or some vex that would point me in the right direction?
  16. Houdini 16 What's New

    Wow! That's some super cool stuff - the animation features look really, really cool, very curious to see how these work!!! Congrats! The ocean on the twisting strip looks really cool, that's a great demo. Compiled SOPs!? Hardware accelerated SOPs? some really interesting stuff in the release!
  17. I'm trying to generated noise that flows along the topology of the geometry. But I'm missing something obvious about how to do that. The red arrows indicate how I'd like the noise to flow. The geo is generated by using the polywire SOP. The only other thing I can think of is using COP to generate a texture map with noise and then read the data from that.
  18. Noise and topology

    Thanks guys, both of these are real interesting ideas.
  19. I'm looking to upgrade my Nvidia Quadro 4000 (which I have never been that thrilled with). Since I have a 2011 Mac Pro, I'm trying to avoid a card that will require me to do things like adding a 2nd PSU (which appears to be a requirement for NVidia cards like the 780), so I'm looking at the ATI 7950. This seems to be a decent compromise, but I'm curious to know if any of you guys have used it with recent versions of Houdini, say H14 or H15 and how did it perform. I found a pretty positive review by someone on the sidefx site for H12, but nothing more recent.
  20. So I broke down and ordered a 970 from macvidcards - fingers crossed, hopefully this will be a nice improvement over the thermal disaster that is the Quadro 4000!
  21. If I have geometry that I'm passing into a CopySop that is changing over time (specifically a basic leaf shape that may have it's shape changed based on stamped values from the copy sop that in turn pull this from attributes on the template points) does it make sense to even use the Packed Geometry option in the CopySOP? IN the sidefx docs I came across this: " This is important to remember when copy-stamping packed geometry. If every instance of your packed geometry is unique, you get no memory or performance benefits. In fact this will use more memory than "real" geometry would, because each packed primitive has its own overhead. " (https://www.sidefx.com/docs/houdini/model/packed#how-to) Since the leaves are different for each template pt, am I sort of defeating the purpose packing them? Or would I use some other workflow? Total number of template points (when the tree is fully grown) is around 110K-150K pts.
  22. Maybe take a look at Peter Quints tutorials on Vimeo - some really good stuff there. 3DBuzz has (or had) a very nice set of stuff.
  23. Thanks TitanX is out of the budget According to the NVidia site (http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-titan-x/specifications) its rated at 250W, but you're running it on a MacPro with no mods to your PSU?
  24. Hamp, thanks for tip. I did look there but it seemed the cards I kept looking at were over the power limit! But the one you mentioned seems to be fine (according to nvidia website it uses 145W). Will definitely look into this guy. How has it performed heatwise? One of the other reasons I want to ditch the Quadro is it's an absolute thermal pig and run's hot as hell. Atom, yes I think the PSU does have that much, apparently (this is what I found online, so take it with a grain of salt) it's an issue with how the Motherboard/LogicBoard are designed by Apple such that the maximum power draw for PCI devices is 225W.
  25. I've got a tree that's generated via the L System SOP. I'm extracting the end points of the branches to grow leaves on them, after running the points through a SOP Solver to add some custom pt attribute data used in growing and animating the leaves. I notice that the point ids kind of jump all over the place as the lsystem grows over time. Is there a way to get a stable set of points such that the oldest point is point 0, and the next is point 1, and so on? Is it just a matter of sorting the points by age?