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Everything posted by Fireandsmoke

  1. It's quite common that Ill set off a render at night only to find out in the morning that it has crashed at some point a short way through. Generally, if I simply restart houdini and render from where it got up to, it will continue without problem. Not sure why this happens, but it does mean over night renders are often a gamble. What I'm wondering is, would it be possible to have some kind of script which detects a crash, reboots houdini with the working project and takes off from the last rendered frame? Would such an idea even be possible?
  2. Script to resume crashed render

    Thanks. Do you know if the free version of Deadline has this functionality?
  3. Convert tris to quads

    As a side note to this which may help someone in the future: if youre wanting to render a wireframe quad look (which is what I was after), using Redshift selecting Rendering an object as Strands will automatically render the wire frame as quads.
  4. Convert tris to quads

    Hi, Im wanting to render a wireframe look of a scan captured asset, but Id prefer to lose all the diagonals and have it in quads.. is there a simple way to convert tris to quads in Houdini 17.5, I cant seem to find it? Thanks
  5. Convert tris to quads

    Cool, thanks for the help
  6. Redshift Proxy Workflow in Houdini

    So does that make the above instruction now irrelevant?
  7. Flickering colours in slow Coloured Smoke

    Hi, I have a simple smoke sim using the Colored Smoke shelf tool which I have run at timescale 0.1, cached out to VDB, and am using Redshift to render. Not problems if I render a sim at full speed, but I'm noticing at this slower timescale I'm getting random flickering of my colours, the saturation dropping away to a varying degree every few frames. https://giphy.com/gifs/FfpdaTVBqu7CVlcAd8 Any ideas?? Thanks for the advice
  8. Flickering colours in slow Coloured Smoke

    Ha..! I will have more of a look tonight as well. Very easy to replicate the problem, just lay down a coloured smoke (via shelf), and gas upres it (also via shelf). Youll see straight away that the upres smoke is black. -J
  9. Flickering colours in slow Coloured Smoke

    Thanks Jesper. Nice try but no cigar unfortunately!
  10. Flickering colours in slow Coloured Smoke

    Well Ive worked out where the problem was coming from, but damned if I know why.. maybe its a bug. For Redshift to render coloured smoke, you have to convert the volume to a VDB (among other things). And basically I'm getting the error if I cache out to VDB and then load the VDB back in and render. If I cache to Bgeo, and then do a the conversion to VDB at render time, no problems. Iv'e been playing all even with the GasUpRes... I LOVE it! It's the first tool I've used in Houdini that makes timescaling a sim do what I want, I wish I'd looked into it ages ago. One question I have, which maybe by chance you can answer... I'm trying to use Gas UpRes with the Colored Smoke shelf tool. but the color is not transferring to the upressed volume. The volumes are created but the Cd values are black. I found a hacky way to use Volume Mix to mix back in a frame with colour from the low res smoke, but I'm wondering if there's a better fix...?
  11. Flickering colours in slow Coloured Smoke

    Will do! It currently imports a reasonably heavy vdb and requires redshift, but the sim is still in there so you can see the settings I used. Thanks Jesper, much appreciated. Ill start looking into Gas Upres and substeps tonight.
  12. Flickering colours in slow Coloured Smoke

    Its at home so I can't double check but 95% sure it was temp
  13. Flickering colours in slow Coloured Smoke

    Ah ok, excellent. I will have a look at that, thanks. When you say cache out subframes, does this have to be done as a .sim, or can you cache subframes into .bgeo or .vdb? My understanding was that a large purpose of the Retime was to avoid having to do all this, relying instead on the method of interpolation (aided by advection), so I'm still curious as to why I'm getting such severe errors (basically its jumping back to some kind of rest state at 5 frame intervals (retiming at a 0.2 speed)). Not to hijack my own thread, but whilst a Retime approach may work, I'm still also curious as to why my original problem is occuring with the flickering color, if anybody has a theory about that...?
  14. Flickering colours in slow Coloured Smoke

    Well I would have thought so, but I've been having plenty of issues with the new Retime node.. I posted about it on sidefx forum but nobody has replied, I keep getting very jittery results such as this: https://giphy.com/gifs/69EhNTJHxxpfE6vHU8 My post is here: https://www.sidefx.com/forum/topic/59932/ One thing I have not been doing though is adding extra substeps to my initial sim. Is that a requirement for a velocity advected retime? And is so is there a relationship between the number of substeps required and the desired retimed speed? Any advice would be helpful, I haven't been getting very good results so far!
  15. Apply detail to smoke using Volume Procedural

    Not sure what you mean to say... if you blank that out, then its just rendering the volume without the procedural.. so naturally it will render the smoke. This issue I'm having is with the volume procedural applied, how do I import that density of the existing smoke into the cvex shader, so I can use the volume procedural to augment my existing smoke.
  16. Hi, This is probably a simple bit of VOPs, but I can't seem to get it. I'm wanting to use a Volume Procedural to add some detail and noise to a low res smoke sim. When I add the noise to the cvexvop, driven by the P and output as density, it is creating noise but filling my whole bounding box, because obviously its adding density driven by noise at every position. How would I restrict it to apply only to the existing smoke, or use the smoke density as a mask? I thought that by first multiplying P by the density would work (such that where smoke density equals 0, no noise would be added) but does not seem to. Thanks for the advice volumeprocedural.hiplc
  17. Apply detail to smoke using Volume Procedural

    It does appear from some reading that when using the Volume VOP Global Parameters inside the CVEX vop it will not import the density of the subject volume, it rather is a blank canvas. So the question is then, how would you import the density of a volume into a CVEX vop?
  18. Apply detail to smoke using Volume Procedural

    Thanks. Yes can see a difference in the viewport but have you tried rendering it? I just get black from the second version (which was also happening when I tried to build the vop according to your picture) An issue seems to be that the "density" inside the cvexvop is not referencing the density of my preexisting volume. Because even the following in the cvexvop will render black.
  19. Apply detail to smoke using Volume Procedural

    Thanks Noobini. I can see your theory here but it doesnt seem to be working for my set up. Would you mind sharing your .hip? Thanks
  20. Compensate for slowing FPS/Timescale

    I've been playing for days and days trying to slow smoke sims for some nice particle advections. They need to be very slow, so the process I've been trying to use is either reducing the timescale, or cranking up the FPS of my timeline. At these slow speeds, it is not practical to find the "look" of my sim, I need to look dev at 25fps, and then slow that version down. But by then slowing down the sim via timescale or FPS, only rarely do I get a result I want. Is there settings with the solver or DOPnet that I need to be adjusting to compensate for the slower speed? Most of the time, a beautifully turbulent and dynamic sim at 25fps often just turns into a hopeless blob at 200+fps or 0.1 timescale. Would love some input on this.. (PS. Im still on 16.5 for now, so the retime node is not an option). Thanks
  21. Houdini 18 Wishlist

    More VR tools, particularly a HMD preview mode, if not from the viewport, then from a flipbook (which would require a top/bottom latlong veiwport display from the spherical camera), or even the render window as a last resort. This would make Houdini infinitely more usable for VR.
  22. Compensate for slowing FPS/Timescale

    For my own understanding, I'd really like to know why changing the timescale parameter changes the look of the sim so much? I thought its function was to scale the time base of everything inside the solver, so why does it then cause such huge change - a basic smoke sim at timescale 0.1, 1 and 5 are all going to look completely different... which makes it kind of useless.
  23. Smoothing volumes

    Thanks for that. Sounds like from some other sources that RS does not have a similar feature. However I need to stick with RS for fast render times. So is brute force voxels the only way for me achieve a dense looking volume with no visible voxels? Are there any tricks or tips you can suggest for keeping my voxel count high and volume smooth, without crushing my pc? Thanks
  24. Smoothing volumes

    Hi, I'm fairly new to volumes so please bare with me.. I'm enjoying creating some cool effects with Houdini volumes and Redshift by simply assigning a Redshift volume material and cranking up both the Scatter and Absorption coefficients of the density to get some cool sci-fi-ey gaseous effects where the volume has an appearance of being quite thick bodied yet translucent. The problem is that dialling up the density like this in the material means the voxels become very defined. So I'm wondering if I'm going about this the wrong way? Or is there a way to smooth my volume out? Im aiming for a 4K output for a big screen so it will need to be very smooth. Ive tried cranking the voxel count to 600 (Max Axis), as you can see below still quite visible. Also tried a Volume blur (and converting to VDB and using VDB Smooth), which helps a bit, but it loses the overall effect and still leaves a moire-ish pattern from the voxels. Thanks for any suggestions
  25. I've got a simple particle setup, a large number of particles being advected by a smoke sim and then cached out to a bgeo. Then loading that into a File sop and using a delete SOP with a Delete by Range (29 of 30) to dramatically thin it out for some close ups. This process has been working well for me across a variety of different particle setups, but for some reason on this shot, my particles hit a certain frame and go bonkers. There is nothing wrong with the actual sim, so I can only put it down to being something to do with the delete SOP. https://giphy.com/gifs/X9jk5OOy7tvaHYtUwR Any ideas what this might be causing this? And any way to fix it without changing my existing geo, as I had already rendered hundreds of frames before I noticed this problem and would love to not have to redo the earlier frames, if possible. Thanks for any advice