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About jimmay

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  • Name Jim May
  • Location Los Angeles
  1. Hi Atom, Yes, that was the first context in which this problem cropped up, as a matter of fact. Using the ROP Alembic node was an attempted workaround at the suggestion of an experienced colleague who was trying to help me out when this issue was threatening to blow a deadline. I'm pretty sure it's the same underlying code anyway. If I have time this week, I might try one of the daily builds, and perhaps ask support if they'd like to take a look.
  2. Hi Atom, That's what I did with the helicopter scene. The original scene is in Apprentice on my personal laptop, so I exported .bgeo.sc to try exporting Alembic from the commercial install on my desktop at work. The spaceship shot was done and tried in Commercial from the beginning. I tried a direct export File --> ROP Alembic node, and also tried inserting an Attribute Delete in between to wipe out all but the most basic attributes prior to export, and a Facet node to see if the normals had anything to do with it - no difference. It blows up after writing out 7 megabytes.
  3. Hi all, I'd like to pick the brains of the TD's out there on exporting RBD dynamic sims out to Alembic, for their experience with the best settings and practices to use. In my limited experience so far, I've found H16's Alembic exporter to be EXTREMELY crashy (build 557). Googling around, however, I don't see hardly any similar complaints, so it means it's probably something I'm doing. The one common thread I can identify is that of the two sims I've had this issue with, both are based on Steven Knipping's Rigids III tutorial, in which there's an extra stage using Point Deform to simulate dented metal. One of them is the actual helicopter crash from that tutorial that I built in Apprentice, exported as .bgeo to a commercial Houdini license for testing - the other is an all-commercial scene of a spaceship exploding. So what suggestions would you have to try and get around this? Scrub attributes? Clean/normal/facet right before the export? The only thing that I've seen work so far was to export an unpacked version of the spaceship to Maya - huge, but it got the shot done. I'm really concerned that something as simple as that helicopter tutorial should be so reliably crashy, though.
  4. ARGH, that's it. Thank you Malf. For reference should any other noobs run into this: there's two places to switch on rest fields: on the container (smoke object) "Add Rest Field" under "Initial data", and on the pyro solver under the "Advanced" tab, "Enable Rest" - this is also where the other controls for rest are located.
  5. Hi guys, Attached is a scene that does something nobody here can explain. It's a fairly simple pyro sim intended to look like a plasma trail from a damaged spaceship. The thing we can't explain, is the fact that it pulses out every 50 frames. Load up this scene, and render frames 51, 101, 151 and the frame renders black. Render the frames around it (or render the whole thing) and you'll see the element simply drops to black for several frames, then recovers for several frames after. The only thing we do that affects it is to shut off the Noises on the fields in the Pyro shader. No amount of messing with the parameters therein has affected it; the 50 frame period is constant. There are no animated properties in the scene that have it either; the spinning emitter runs from 1 to 120. The issue is the same with H16 style Pyro shader, and with the earlier H15.5 pyro in shopnet when it's set up with similar settings (both are present in the attached scene). I'm using those noises b/c for the life of me, I can't find any way to do detailing displacements of volumes at the shader level after the fact - googling such just gets me hits on how to do it for Arnold, or in the older shopnet. I'm very much a noob, and mostly have done shader work in H16's new context. My supe likes the results we have here, but if I shut off the Pyro shader field noises I lose the look. Any help appreciated - including workaround pointers on how to do my own volume displacements in shaders, post-pyro sim. Trail_v04.hip
  6. thankyouthankyouthankyou woodenduck. I really love the power and capability of Houdini.... but sometimes it reminds me of why I got out of programming 25 years ago
  7. Hi all, I'm setting up a basic missile trails test, where the missiles are emitted by one popnet "missiles", and the trails from a second popnet "trails" I'd like a consistent amount of particles per missile as more are fired, so after some reading around I set up npoints("obj/geo1/xxxxx") in the Impulse Count for the trails popnet. However, npoints consistently evaluates to 0. I tried pointing it to a poly sphere instead of the "missiles" popnet, and it still evaluates to 0. Any suggestions? I found this on H16 build 504, updated to 557, no change. npoints.hipnc
  8. Hi Matt, Raytracing Bias might be worth looking at. I have it set very small (.0001) in order to keep small water droplets on the label from "punching through" it. When I Googled around, I couldn't find any information on what the consequences were for going too far in that direction. This scene is real-world scale, using meters. I've not tried switching it to centimeters. Light quality is set to 8 for the softboxes, and they have HDR textures on them. There is a "self shadow" option for the light that is on by default, I could try that too. But beyond that, the bottle "backlight" is emissive, so it should't be catching any shadows at all. I'll have to set a camera back there to look at it and see if it does anything. It might be a while before I do, though, as I'm knee-deep in an RBD sim at the moment.
  9. Hi all, Just in case anyone else runs into this: 1. Yes, rookie Apprentice users can submit bugs. SideFX is great, they were quick to respond with a workaround. 2. Nested Dielectrics must be turned on for the transmission tinting to work in PBR, even when not nesting, in this build. I take this as meaning, just turn it on right away and leave it there. Editing to Add: Here's the first test render of the shot I was building. Would anyone have suggestions on what to tweak to fix the "shimmering" in the beer bottle backlight (and apparently the area light reflections)? That's done via a luminous sphere using incident-angle shading. Should I bump up the Reflection and Refraction quality sliders? Those were both set to 8, and Stochastic Transparency also set at 8, with all else at defaults. Possibly relevant: the backlight sphere is using a Material Builder shader, while everything else is Principled Shaders, and it's actually behind the set - I've set up render flags so the set is unseen in secondary rays. Mantra PBR.
  10. Hi Houdini folks, I'm trying to build a beer bottle product shot in Houdini 16 to learn the new materials system. I've run into a weird issue with the principled shader implementation of the brown glass. It renders the absorption of the glass incorrectly when in the Mantra physically based renderer, but looks right in RayTracing mode. In PBR mode, the first two "hits" of rays in tinted glass don't get tinted. So, for a tinted glass tumbler, light that passes side-to-side through the thick bottom, without going through the empty part of the glass, *should* have the deepest color, having travelled through the most glass. However, in PBE mode it renders perfectly clear. Light passing through the middle of the glass should have less tinting, since it passed through the air inside the glass - but since it has four hits, two for each side, it does show tint. In raytracing mode, it renders correctly. First: What settings do you think I should check before wondering if this is a bug? I'm relatively new to Houdini, but not to rendering in general. The limits are at default settings. Second, may I submit bugs as an Apprentice user? Asking here b/c the SideFX forums are currently broken for me - first posts need to be moderated first, supposedly, but that can't happen b/c it never submits anything - just keeps kicking it back for editing.