Render problem: shimmering

[rusty]

Hi,

 

I'm a 'rusty' old 'old timer' but I'm back and trying to animate and get some video of a bunch of models (space ships for the most part) created for my last AM project (a book trailer for my sci-fi book). To give credit where due, some models were created by AM users from all around the world. I'm using V14 NetRender (I plan to upgrade shortly), however, so far, I've only tried rendering right out of AM.

 

I'm encountering a problem I've not seen before and it's happening on all three of the scenes I've tried to render (so that means 3 different sets of prj files, model files, etc). Things are 'shimmering' on finals renders (this best description I can come up with). As I said, I've just been rendering from AM (not NetRender). I see this 'shimmering' within complex geometry, materials and images used as decals.

 

What I've tried so far:

* The ships had to be scaled way up in the Chor so I tried rendering with no scaling but there was no difference.

* I tried both multipass off and with 9 passes, softness on.

* The render options 'Alpha Buffers' and 'Draw Particles / Hair' make no difference.

 

The target is YouTube, perhaps HD (though honestly I'm not sure what HD really means in technical terms). I've included the render settings below and my systems information is also below. The output is pretty large as is but I can post an example if needed (I'm hoping this is a simple problem everyone knows the answer to!!!).

 

Any suggestions will be greatly appreciated!

Rusty

 

Render Settings:

30fps

Uncompressed TGA

Resolution: 1280x720

Gamma: None

Buffers: Alpha

Quality: Final

Multi-Pass: *

Motion Blur: On (defaults)

Shadows: On (defaults)

Reflections: On (defaults)

Draw Particles / Hair: **

 

All else off.

 

* Original renders had multipass turned off. I tried rendering with 9 passes/softness=on but this made no difference.

** When needed. No difference.

[robcat2075]

hey, the post made it!

 

Can you show a few frames that demonstrate the problem?

[jakerupert]

Have you checked for internal patches?

Often theycan cause rendering-artifacts and if you use models, other people made,

they could easily have creeped in, especially if the models were very complex.

[robcat2075]

My first guess is that you need more passes.

 

9 pass is just 3x3 anti-aliasing which is less than the regular render (4x4)

 

 

 

minute detail is always a challenge for CG.

[pixelplucker]

Coplaner faces could cause that. I have had a similar issue a while back and it turned out I had hit "E" in the model window by mistake and I use 0 offset many times. moving a cp should reveal another cp in the same spot if this is the case.

[HomeSlice]

"Shimmering" could mean many different things. Like Robcat said, it would help if you show 5 or 6 seconds of footage which illustrate the problem. But if it is anything like the "shimmering" in some of my past projects (rendered with 9 passes), one thing that helped with my issue was to add a Denoise filter in my editing app when I exported the edited animation. A:M also has a Denoise filter that works pretty well too.

[mouseman]

Coplaner faces could cause that. I have had a similar issue a while back and it turned out I had hit "E" in the model window by mistake and I use 0 offset many times. moving a cp should reveal another cp in the same spot if this is the case.

I did that recently, as well.

[rusty]

Coplaner faces could cause that. I have had a similar issue a while back and it turned out I had hit "E" in the model window by mistake and I use 0 offset many times. moving a cp should reveal another cp in the same spot if this is the case.

 

Hi,

Thanks for all the replies! Lots of good ideas and I will post an example. Something is nagging me at the back of my mind with this problem... I'm almost sure I've hit this before and although I can not remember anything about that time something makes me think that a) it was an obvious problem and, it had something to do with compression or encoding. That may all be horse s__t but that's what keeps coming to mind.

 

Coplanar faces??!!??!!?? I often discover to my horror that a model is all messed up with cps and splines overlaying each other... I usually find it by accident or when trying to texture a model. It makes no sense the way these duplicate overlaying cps and splines are connected either... they are all part of the same model (all connected) but I don't think selecting the model and doing 'e' would produce the crazy stuff I see. Anyway, this really caught my eye as when I discover such a problem I must either delete it (the model) and rebuild and re-texture and re-rig and... (you know the drill), or... slowly and painfully find all 'coplanar' cps/splines and delete them (I know of no easier way to fix the problem I see). I have no idea how such a thing can happen. Oh, I'm pretty sure it's something I'm doing but what I don't know. Any additional information you have would be appreciated!!

 

Sadly, if this is the case, then every part of 4 large and complex models is messed up. I almost don't want to check! :-o

 

Rusty

[rusty]

Hi!

 

Darn... I used AE to take the large TGA files from AM and crop out a small part... I am fairly sure I correctly set AE so 'no' processing took place but... I'm not 100% sure. Looks the same to me.

 

I could use PS to reduce the TGAs size but some of the artifacts might vanish.

 

But, the only thing that really makes sense (given that I'm lazy) is to just put the tga output from A:M (220 frames/30fps) on my site.

 

My AE reduction (see 1st paragraph) is already out there if you're interested or want a smaller download or don't want to wait for the above. The URLs for both are:

 

220 tga frames from AM (file size: 368,050KB)

http://www.virtualmediastudios.com/ShimmerTest_TGA.rar

 

Smaller cropped by AE (file size: 119,358KB)

http://www.virtualmediastudios.com/ShimmerTest_AE_TGA.rar

 

Please let me know if you encounter any problems with the downloads or compressed files.

 

In the full AM video (ShimmerTest_TGA.rar) you'll see this:

 

The geometry up close looks like this:

 

I'm going to render this same sequence in NetRender but I will probably take me a day to get it going again.

 

Thanks!

Rusty

[HomeSlice]

I'm pretty sure a little bit of Denoise will get rid of the shimmering in all those cases. Try it on a couple hundred of the frames you have already rendered (save the processed images under new names).

 

If you want to try the A:M denoise filter, I believe the properties are described in the attachment to this post:

http://www.hash.com/forums/index.php?s=&am...st&p=327831

[Rodney]

I tried a couple different approaches in A:M but didn't have time to close the loop.

Denoise worked pretty well though and better than just Blur alone.

 

As I see it there are two issues:

- Shimmering - Due to high frequency of the surfaces (i.e. lots of surface noise)

- Strobing - Due to movement/rotation of parallel lines (grids and girders)

 

I had more success with the Shimmering than I did with the Strobing.

 

 

I recall reading an article about dealing with high frequency surfaces before that suggested not simply burring the images but rather feeding a lot of noise back at/into those surfaces. I thought perhaps this is what the Denoise process does but it appears to blur and blend the results also. If the Denoise settings are set low enough that it won't smudge the detail out of your images, I agree with Holmes that Denoise may be your solution.

[rusty]

Hi!

 

Well, first thank all of you for the time and effort you've put into helping me.

 

If you find that article Rodney, let me know... sounds counter-intuitive which is why it might just work LOL. And 'good eye' on the shimmering and 'strobing' problem ids.

 

I will try what you've suggested as well as a few ideas I have and will keep you posted. I think simply creating an avi or mov will make the problem vanish! I have a lot going on and haven't even tried this yet! If not, beyond de-noise and blur there's possibilities with over-sampling and even just lighting and staging. I'm already in the process of replacing materials with images. This will help. For many years I just never used materials then... I got lazy... the upshot is; I don't have a lot of experience with them.

 

Cheers,

Rusty

[robcat2075]

yup, you got tons of small fine details there.

 

That rusty texture on the rocket nozzles... that's got a noise component, what are the "octaves' set to?

[rusty]

yup, you got tons of small fine details there.

 

That rusty texture on the rocket nozzles... that's got a noise component, what are the "octaves' set to?

 

Had to look... that model is old... circa 2006 maybe, with some upgrades a couple of years ago. That is a SimbiontAM material called metalScratchSteel. I'm not a 'material' person. Although I know what can be done with them (from Mastering Materials CDs watched) if I use them at all I just drag and drop and sometimes scale. As far as swapping images for materials, I've been working on several newer models and haven't even considered making changes to that one... in fact, I'll do my best to avoid it.

 

But the question is, why do you ask?

 

 

Rusty

[robcat2075]

The more octaves, the more detail in the noise pattern. Detail that is a pixel or less onscreen is very difficult for the renderer to interpret consistently as it moves around.

 

For example both of these look gray from a distance but the top is really black and white dots. As it moves in front of the camera it's hard for the renderer to sample those black and white dots and produce the exact same shade of gray each frame.

 

 

 

Less complicated textures might give the same final appearance but with less flickering.

[rusty]

Ha! How do you use the AM de-noise?? Sat down to try it but chores call and I see no easy 'add denoise'... bummer. I'll have time later... rendering to final (the way I do it) reduced the shimmering by at least 50%. Not much for the strobing.

 

r

[mtpeak2]

Denoise is a camera post effect.

 

Right click on the post effect folder and choose new post effect. Right click on the post effect and choose denoise. Drag the post effect onto the camera in the chor. Make sure you set the camera to render post effects in the render option.

[rusty]

Denoise is a camera post effect.

 

Right click on the post effect folder and choose new post effect. Right click on the post effect and choose denoise. Drag the post effect onto the camera in the chor. Make sure you set the camera to render post effects in the render option.

 

Exactly what I did just guessing... except for the last step, however I can see the effect so its working (render is 50% done).

 

Thanks!

r

[HomeSlice]

You may want to render normally and apply the post effect to your already-rendered frames. That way, if you decide later that you want to try different settings, you don't have to re-render the whole thing. How to do that is covered in the second part of this tutorial:

http://www.hash.com/forums/index.php?s=&am...st&p=252870

[ypoissant]

Sorry, I will get a bit technical but that is a technical issue.

 

If your on-screen details (geometry or texture) are smaller than your render sampling resolution then you will get that sort of shimmering.

 

Sampling resolution: Say you multipass with 9 passes, then you have a 3 x 3 sampling per pixels. Then if your details are smaller than 1/3 pixel square, you will get shimmer.

 

For geometry size issues, there are no other solutions to this shimmering than sample at higher resolution. This mean increasing the number of passes.

 

For image textures, one other solution is to use an image of lower resolution or do a blur pass on your image. You would need different versions of the same image with different resolutions or different level of blur to match the closeup-ness of your shots.

 

For procedural texture, you got to be an expert in that sort of thing. Basically, you need to remove the tiny details in the texture generators. Looking at the octave is a good hint but there is much more to it. Unfortunately, you can't blur procedural textures. But usually, you can replace a procedural by an image texture. Procedurals are very prone to shimering. I'd recommend replacing all the procedural with images. One way of doing that is to render the procedural from your geometry at the highest resolution and then remap the resulting image.

[robcat2075]

thanks for dropping in to clarify that, Yves!

[jakerupert]

Thank you Yves for your info!

 

Don`t you have a website anymore?

 

What became of your lovely meshlady?

 

;>) Jake

[ypoissant]

Don`t you have a website anymore?

 

What became of your lovely meshlady?

 

The host is ready to receive the web site but I can't seem to find time to upload and set it up. Part of my disinterest is that I haven't updated the site for years and it really doesn't reflect my current interests and work anymore and making it up to date would require much more time than I have available right now.

 

The lady is sleeping somewhere on some hard-disk. It was left in a limbo/"work in progress state" when I started to modify the anatomy and then some other priorities came in. As it is, right now, I'm not satisfied with the anatomy and proportions at all. I don't see the time when I will start working on it again. I tried to match some backup models with the dates when I posted the renders here on this forum but I can't find that version. Don't know what happened then. And sorting this mess out would again require more time than I have available.

[jakerupert]

So, you are still using AM?

 

Maybe we will hear more from you again with 16 coming up, would be great.

[mouseman]

Yves, we always love reading what you have to write! You definitely have a fan base here!

[ypoissant]

Guys, I appreciate your nice words. But let's not hijack Rusty's thread. I replied Jakerupert privately. All goes well. I just don't have much time available these days. Work take all the place.

[rusty]

Sorry, I will get a bit technical but that is a technical issue.

 

If your on-screen details (geometry or texture) are smaller than your render sampling resolution then you will get that sort of shimmering.

 

Sampling resolution: Say you multipass with 9 passes, then you have a 3 x 3 sampling per pixels. Then if your details are smaller than 1/3 pixel square, you will get shimmer.

 

For geometry size issues, there are no other solutions to this shimmering than sample at higher resolution. This mean increasing the number of passes.

 

For image textures, one other solution is to use an image of lower resolution or do a blur pass on your image. You would need different versions of the same image with different resolutions or different level of blur to match the closeup-ness of your shots.

 

For procedural texture, you got to be an expert in that sort of thing. Basically, you need to remove the tiny details in the texture generators. Looking at the octave is a good hint but there is much more to it. Unfortunately, you can't blur procedural textures. But usually, you can replace a procedural by an image texture. Procedurals are very prone to shimering. I'd recommend replacing all the procedural with images. One way of doing that is to render the procedural from your geometry at the highest resolution and then remap the resulting image.

 

Yves,

 

Thanks for the info! I'm working on replacing the materials with images now. After that I'll have to get all my slaves up and running to do more passes.