Pyro rendering

[Guest]

Hi,

My name is Jonas.

I am fairly new to Houdini, but I definitely feel that I'm learning.

However, now I have a problem.

When I try to render a pryo simulation of mine, I get some pretty harsh edges.

It's not for a specific project, it's generally.

I've tried to change almost all of the parameters, but it doesn't work...

And when it have been working better, I have gotten some insane render times.

Any ideas for what to change?

Again I am fairly new, so I do not know what to upload to you guys, what info do you need?

for my tests I have just been using a sphere, which I've applied the billowy smoke to.

I've decreased the division size to 0.05 and my render is set to 32x32 in pixel samples.

My volume quality to 1, general shading quality to 10.

What else to do?

Cheers,

Jonas Jørgensen

[Skybar]

32x32 pixel samples is.. insane. What is the problem exactly? Post an image or something so we can see.

[Guest tar]

Jonas, pixel samples are multiples of the final pixel. When you put 32x32, that means for every pixel that you see in the rendered image 32 are rendered! You are rendering an image 32 times the size of the final image!. i.e. you HD render of 1920x1080 is rendering at 61,440 x 34,560.

That is probably the main reason for the slowness.

[Guest]

Yes I get that, which to me seemt crazy aswell.

However, that was how I got rid of the grain of the first render, but then my render got really blocky, like all the edges were very boxy.

Any tutorials on how to get a good Pyro render and maybe how to set a good pyro sim up?

Cheers

[LouisXIV]

Without an image its a bit hard to know what you mean.. But it sounds like the filter settings on the pyro fields, you are rendering is too harsh. Regarding the noise, did you try raising the transparent samples under the sampling tab in the mantra node?

[Guest]

First off, here's the project file. It's still rendering, so I will post the image as soon as it's done.

So what of the settings are off?

most basic setup possible I guess, but still I can't get it to work.

How would you get the best render out of that?

Cheers and thanks!

example.hipnc

[Guest]

And here is the picture, I didn't let it finish the render, since it have already taken 40minutes...

[Skybar]

First thing would be to increase the Transparent Samples, something like 10 seems fine. Then reduce the Noise Level and increase Max Ray Samples until you are satisfied with time/noise-ratio. Noise Level basically sets the limit to how much noise is acceptable, and shoots more rays up to the maximum where it's needed. Then you can increase your Pixel Samples to something like 5x5 (=25 samples/pixel) or 6x6 (=36 samples/pixel). Higher pixel sampels increases the rendertime exponentially so you dont want to go too high. You can also increase the Volume Quality if you want.

Also, on your Geo node containing the volume (import_pyro_build in this case), you can go the the Render tab and set the Volume Filter to "Gaussian" - this will smooth out the volume a bit getting rid of obvious voxels in the render. Adjust the Filter Width there accordingly, but the default value should be fine and you don't want to go too high since you lose detail.

For the render engine I choose PBR (physically based rendering). Heres a quick test that took ~3min to render:

[Guest]

Thank you very much, I will definitely look in to that, then...

Any tips for where to learn Houdini, the best way?

I am currently taking 2 fxphd courses for Houdini.

Cheers

[Guest tar]

You could allocating your learning time as 30% on tutorials, 30% on structured learning, 40% playing. Each area informs the other areas where you need to skill up.

[Guest]

Thanks a lot, seems like the best way to learn Houdini.

Cheers