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About Fireandsmoke

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    Sydney, Australia
  1. 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.
  2. 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?
  3. 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.
  4. 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
  5. 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
  6. 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.
  7. 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.
  8. 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
  9. 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
  10. 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
  11. Compensate for slowing FPS/Timescale

    Thanks Atom, this looks good. Have you used this setup before? Ive tried copying this retime setup into my own pyro sim but its not working as in the original .hip, just plays back both at the same speed. EDIT: Just noticed that this actually involves the installation of a custom asset library.. then it will work..
  12. 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
  13. Make smoke follow a curve

    Many thanks for the link, good find!
  14. Retime sim

    I've seen a few responses to this question, but still am having no luck, wondering if someone can hold my hand and give me some specific instructions. I simply want to retime a VDB of smoke to make it slower, interpolating between frames. I've got a VDB which I've cached out and loaded back in via File SOP. Now I've added a Time Blend, and then a Time Shift. In the TimeShift I've changed the Frame expression to $F*0.5 and unchecked Integers. I'm still not seeing any interpolation between frames. What settings do I need in my TimeBlend for this to work? Thanks a lot
  15. Make smoke follow a curve

    I'm trying to make billowing smoke follow a spiraling curve, kind of as if a tornado did a corkscrew. I know with POPs this is quite easy using Curve Force, the particles really adhere to the tube. But using Gas Curve Force with my smoke is just causing little wisps to get sucked in the direction of the curve rather than causing suction to the mass of the volume. Is there a better way I should be approaching this? Thanks for the advice