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Fireandsmoke

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About Fireandsmoke

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    Peon

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  • Name
    JHeks
  • Location
    Sydney, Australia
  1. 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
  2. Flickering colours in slow Coloured Smoke

    Thanks Jesper. Nice try but no cigar unfortunately!
  3. 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...?
  4. 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.
  5. Flickering colours in slow Coloured Smoke

    Its at home so I can't double check but 95% sure it was temp
  6. 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...?
  7. 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!
  8. 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
  9. 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.
  10. 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?
  11. 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.
  12. 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
  13. 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
  14. 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.
  15. 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.
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