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Technical Discussion » Flip Splash leaves little drops almost static in the air
- AndreasOberg
- 117 posts
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I still have this issue. The remove points works pretty well (I have modified it a bit) but it seems to be one frame behind. So I can see the particles stop and then they disappear the next frame. So looks a bit glitchy.I was wondering if this could be a bug in the Flip SOP since its so new?
Technical Discussion » Best way to cache a Flip in the SOP
- AndreasOberg
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Hi,
I was wondering what the best way to cache a flip in the SOP context.
I can capture the geometry easy but I want to cache the particles too.
I was wondering what the best way to cache a flip in the SOP context.
I can capture the geometry easy but I want to cache the particles too.
Technical Discussion » Flip Splash leaves little drops almost static in the air
- AndreasOberg
- 117 posts
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Enivob
I can't seem to reproduce your issue. Perhaps you have the Cache memory setting too high? You may be running out of physical memory as the simulation continues. Try resetting it to the default, 5000MB and simulating again..?
Thanks for checking!
Oh, that is really strange. Can you double check in the Solver that the wrangle node is disabled (so it does not delete particles moving slowly). I did put a node in there that would delete slow moving particles. I thought it was disabled before uploading but best to be sure.
I have 256GB so would think it would be enough on this machine, but I can try with less cache.
When I analyze the Geometry Spreadsheet I see that the v.x and v.z is 0.0 for these particles. Also the L attributes are all 0.0 as well which is odd. However the particles are not dead.
I wrote this in a wrangle node. It deletes everything moving very slowly in x and z direction.
if(abs(v@v.x)<0.001 && abs(v@v.z)<0.001 && abs(v@v.y)<1.0) removepoint(0,@ptnum);
Edited by AndreasOberg - 2022年9月13日 10:28:05
Technical Discussion » Flip Splash leaves little drops almost static in the air
- AndreasOberg
- 117 posts
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To me it looks like the droplets are hitting something, but its just in the middle of the sim. What could it be?
Technical Discussion » Flip Splash leaves little drops almost static in the air
- AndreasOberg
- 117 posts
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Enivob
Are you sure they're not colliding with the closed wall of your domain?
They are spread out all over I cannot see that is in the edges, plus I do not have collision on the edges.
Deleting based on speed was not great because it will kill them when they are turning around in the top.
I'm uploading the sim here. You will begin seeing the problems around frame 50. Here is an image that shows all the stuck droplets.
Image Not Found
Edited by AndreasOberg - 2022年9月13日 08:57:18
Technical Discussion » Flip Splash leaves little drops almost static in the air
- AndreasOberg
- 117 posts
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I added a wrangle that deletes the particles when they flow slowly, but not that happy with this situation.
It seems a bit that the particles suddenly just stop, looks real bad.
It seems a bit that the particles suddenly just stop, looks real bad.
Technical Discussion » Flip Splash leaves little drops almost static in the air
- AndreasOberg
- 117 posts
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Hi,
I'm working on a flip splash. One problem I have is that in the end of the lifetime I get these little drops that almost stop in the air and slowly slide down, looks a bit like a drop on a window slowly falling down. Any idea what is going on?
Could it be that they get 0 mass because they are so small so that is why they stop? They do not collide with anything.
One solution I thought of is to delete particles that have very low velocity, but that could introduce other problems maybe.
Cheers,
Andreas
I'm working on a flip splash. One problem I have is that in the end of the lifetime I get these little drops that almost stop in the air and slowly slide down, looks a bit like a drop on a window slowly falling down. Any idea what is going on?
Could it be that they get 0 mass because they are so small so that is why they stop? They do not collide with anything.
One solution I thought of is to delete particles that have very low velocity, but that could introduce other problems maybe.
Cheers,
Andreas
Technical Discussion » Possible to get more information during renders?
- AndreasOberg
- 117 posts
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Yes that one has a bit more info but when I use Redshift they do not seem to have that option for some reason. Not from the ROP at least.
Technical Discussion » Possible to get more information during renders?
- AndreasOberg
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Hi,
I find the progress bar in Houdini really basic. Is it possible to get more information. For example last frame render time, average frame render time, estimate render time of sequence.
Also after the render has been done, is it possible to actually get the render time somewhere? The way I use these days is I look at the time stamp on the files so see how long it took.
I find the progress bar in Houdini really basic. Is it possible to get more information. For example last frame render time, average frame render time, estimate render time of sequence.
Also after the render has been done, is it possible to actually get the render time somewhere? The way I use these days is I look at the time stamp on the files so see how long it took.
Technical Discussion » Help with choosing a CPU
- AndreasOberg
- 117 posts
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Good luck with your purchace.
From what I remember the 5950 were 50% faster per core than our 64 core which is very impressive.
Do not forget a good GPU to render with. I almost never render with the CPU any more. You can snatch up 3090 cards for good prices now, but the slower like 3080 or last gen 2080 are great for rendering.
From what I remember the 5950 were 50% faster per core than our 64 core which is very impressive.
Do not forget a good GPU to render with. I almost never render with the CPU any more. You can snatch up 3090 cards for good prices now, but the slower like 3080 or last gen 2080 are great for rendering.
Technical Discussion » Possible to cache velocity at half resolution for volumes?
- AndreasOberg
- 117 posts
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All great suggestions. I will change to working with Pyro in SOP. Feels a lot finally to finally be in one place instead of jumping around.
I thought a bit about it and I realized I do not want the velocity grid to be lower resolution in the simulation. However when caching the final VDB to disk THEN I would like to lover the resolution of the vel grid since I only use it for motion blur. I would think that motion blur does not need to be that detailed, or?
1)
I'm thinking
1. Split out the vel property to another vdb.
2. Half resolution of vel vdb. Also would the vel not be possible to have in 8bit instead of 16bit? How can you convert that? I know how to convert to 16bit, but not sure about 8bit
3. delete vel in original vdb
4. Now cache both density and vel vdb to disk
5. merge them together
However this looks like it could be quite a bit slower, if the operations are slow may be too much pain.
2)
Also another question with motion blur. Is it possible to use several steps of attribute for the motion blur. I find that the motion blur is always very straight, while it would look nicer if it was more "bent" basically reading from more steps or even sub steps.
3) Another question. When you guys render for movies in say 2k. What resolution would you simulate the volume in if it will cover the whole screen? To me it seems like 1/3rd voxels will cover the resolution quite well with motion blur.
So if the render resolution is 2000 then a 700x700x700 voxel grid will be enough?
Cheers,
Andreas
I thought a bit about it and I realized I do not want the velocity grid to be lower resolution in the simulation. However when caching the final VDB to disk THEN I would like to lover the resolution of the vel grid since I only use it for motion blur. I would think that motion blur does not need to be that detailed, or?
1)
I'm thinking
1. Split out the vel property to another vdb.
2. Half resolution of vel vdb. Also would the vel not be possible to have in 8bit instead of 16bit? How can you convert that? I know how to convert to 16bit, but not sure about 8bit
3. delete vel in original vdb
4. Now cache both density and vel vdb to disk
5. merge them together
However this looks like it could be quite a bit slower, if the operations are slow may be too much pain.
2)
Also another question with motion blur. Is it possible to use several steps of attribute for the motion blur. I find that the motion blur is always very straight, while it would look nicer if it was more "bent" basically reading from more steps or even sub steps.
3) Another question. When you guys render for movies in say 2k. What resolution would you simulate the volume in if it will cover the whole screen? To me it seems like 1/3rd voxels will cover the resolution quite well with motion blur.
So if the render resolution is 2000 then a 700x700x700 voxel grid will be enough?
Cheers,
Andreas
Technical Discussion » Possible to cache velocity at half resolution for volumes?
- AndreasOberg
- 117 posts
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tamte
in case you are using Pyro Solver SOP you can find the same options from embedded Pyro Post Process in Output Tab
- check Convert to VDB
- Use 16bit float
- and Resample Volumes, potentially Cull Volumes
since 19.5 you can also sim with half res velocity that can give you performance boost, but you would have to test for your case as the it would obviously change your simulation look a bit even though there are claims that for hi res sims the difference is acceptable
you'll find it here: Setup/Velocity Voxel Scale
Thanks guys, very helpful.
I realized why it was so slow. The simulation was 1.9 billion voxels. Interesting because the VDB resolution was only 400 million voxels but when I checked the pyro node it was 1.9. I was doing render tests at 2048x2048 with a smoke covering the full screen in Redshift and wanted to see the maximum resolution that would be meaningful. I struggle with simulating since it crashes Houdini about 60% in the simulation even though I have 256GB of RAM. It seems its just running out.
I found a tutorial that helped so I did these. Does it make sense? The files got a lot smaller.
- import pyrofields
- convertvdb. still 32bit float
- Primitive properties. In it I set VDB to Write 16bit floats.
- File cache
Velocity. I only use velocity for motion blur in Redshift, so I would think it does not have to be that highres.
This is an older simulation that I reuse so its not a SOP. I should probably convert it though. We often have old simulations we really like and keep reusing them so they are not always updated to the new cool methods.
Technical Discussion » Starting File Cache after it has been uninterupted
- AndreasOberg
- 117 posts
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I use File Cache to save a volume simulation that I'm working on.
I did half of the simulation but had to abort. Now what is the best way to start from the place I was before?
I tried entering frame 30, but then it redid the whole simulation up to frame 30 which took a lot of time.
I guess the pyro could not calculate correctly because it did not know the status on frame 28 so it had to redo the whole thing.
One way could maybe be to cache to disk the Simulation node? That way the simulation is cached, and then it would be easy to cache the final result. with the File Cache.
Thoughts?
Andreas
I did half of the simulation but had to abort. Now what is the best way to start from the place I was before?
I tried entering frame 30, but then it redid the whole simulation up to frame 30 which took a lot of time.
I guess the pyro could not calculate correctly because it did not know the status on frame 28 so it had to redo the whole thing.
One way could maybe be to cache to disk the Simulation node? That way the simulation is cached, and then it would be easy to cache the final result. with the File Cache.
Thoughts?
Andreas
Technical Discussion » Possible to cache velocity at half resolution for volumes?
- AndreasOberg
- 117 posts
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I'm working on a larger sim with 400 mil voxels and the total cache is 1TB large for 100 frames.
I have density and vel.
I wonder is it possible to reduce the file size somewhat? Compression maybe?
For example lower the resolution of vel to half resolution and then add it back later with the more high resolution density. I only use vel for motion blur.
Cheers,
Andreas
I have density and vel.
I wonder is it possible to reduce the file size somewhat? Compression maybe?
For example lower the resolution of vel to half resolution and then add it back later with the more high resolution density. I only use vel for motion blur.
Cheers,
Andreas
Technical Discussion » Karma Rops always renders in 1280x720, why?
- AndreasOberg
- 117 posts
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jsmackAndreasOberg
2. A general thing I noticed with Karma and rendering, I mostly render volumes. In the viewport and Mplay I can render an image in 10 seconds. But if I render out a frame range it will usually take 1 minute per frame.
I generally find that previewing is really fast but rendering a frame sequence to harddisk takes hours. Any thoughts why this could happen?
The preview is fast because the volume is already in memory and can be rendered immediately. When rendering a sequence, the data has to be read in, written to a usd file, and the renderer started again with the usd file after each frame. The teardown and io can sometimes take most of the time when renders are short. You might have a faster render if you pre-cache your usd scene, so that it doesn't have to rebuild the scene for each frame. Also, the usdrender rop has an option to 'render all frames in a single process,' this prevents the renderer from having to quit and restart after each frame and load the scene again. (note that to use this feature, the output file path must use the "<F4>" token and not "$F4" which doesn't work with 'all frames' mode.
That is interesting.
- You might have a faster render if you pre-cache your usd scene, so that it doesn't have to rebuild the scene for each frame.
That sounds like a good idea. Do you mean just use the Cache node?
- the usdrender rop has an option to 'render all frames in a single process,' this prevents the renderer from having to quit and restart after each frame and load the scene again.
Would you mind explaining where I find this setting. Looked everywhere and cannot find it.
Thanks. It would be nice if one could push down these quite simple renders so they do not take an hour.
Work in Progress » Heightfield terrain - Redshift
- AndreasOberg
- 117 posts
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Technical Discussion » Help with choosing a CPU
- AndreasOberg
- 117 posts
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I would go with the AMD, the 7000 would be quite a step up so if you want wait that one will be a step up.
We use the 64 core Threadrippers, which are great because of their cores but a collegue have used the 5950 and we compared them. The 5950 were considerably faster per core than the 64 core, more modern design and higher frequency.
Used AMD for a long time, never disappoints.
Best wishes,
Andreas
We use the 64 core Threadrippers, which are great because of their cores but a collegue have used the 5950 and we compared them. The 5950 were considerably faster per core than the 64 core, more modern design and higher frequency.
Used AMD for a long time, never disappoints.
Best wishes,
Andreas
Technical Discussion » Karma Rops always renders in 1280x720, why?
- AndreasOberg
- 117 posts
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I'm uploading a smoke example that has this problem. Preview 11 sec, but render to disk 1-2min per frame
I tested and in MPlay it renders image frame 10 in 7seconds. However it takes 10 seconds after I click render to open MPlay so I guess the total is 17sec.
To render out the first 10 frames takes 2min 40seconds for me. If I jump between frames in Solaris preview the image loads very fast in the previs, no start time, it takes about 4 seconds to render each frame, but I guess the preview is showing lower resolution.
I tested and in MPlay it renders image frame 10 in 7seconds. However it takes 10 seconds after I click render to open MPlay so I guess the total is 17sec.
To render out the first 10 frames takes 2min 40seconds for me. If I jump between frames in Solaris preview the image loads very fast in the previs, no start time, it takes about 4 seconds to render each frame, but I guess the preview is showing lower resolution.
Edited by AndreasOberg - 2022年9月2日 11:18:20
Technical Discussion » Karma Rops always renders in 1280x720, why?
- AndreasOberg
- 117 posts
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Ok, that is great to know. Thanks guys!
A few other issues I have
1. If I click on render in background on the ROP (works fine in Solaris) it will game me a Syntax Error. Does that happen to you too?
2. A general thing I noticed with Karma and rendering, I mostly render volumes. In the viewport and Mplay I can render an image in 10 seconds. But if I render out a frame range it will usually take 1 minute per frame.
I generally find that previewing is really fast but rendering a frame sequence to harddisk takes hours. Any thoughts why this could happen?
A few other issues I have
1. If I click on render in background on the ROP (works fine in Solaris) it will game me a Syntax Error. Does that happen to you too?
2. A general thing I noticed with Karma and rendering, I mostly render volumes. In the viewport and Mplay I can render an image in 10 seconds. But if I render out a frame range it will usually take 1 minute per frame.
I generally find that previewing is really fast but rendering a frame sequence to harddisk takes hours. Any thoughts why this could happen?
Edited by AndreasOberg - 2022年9月2日 11:15:57
Technical Discussion » Karma Rops always renders in 1280x720, why?
- AndreasOberg
- 117 posts
- Offline
Hi.
I have been using the Karma ROP in 19.5 but have several confusing things happening.
The main one is that no matter what resolution setting I use it always renders in 1280x720.
I tested changing resolution in the Common Settings and also in the Camera but still the same result.
Any ideas what is wrong? I uploaded a simple test scene.
I have been using the Karma ROP in 19.5 but have several confusing things happening.
The main one is that no matter what resolution setting I use it always renders in 1280x720.
I tested changing resolution in the Common Settings and also in the Camera but still the same result.
Any ideas what is wrong? I uploaded a simple test scene.
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