Problem with Rendering

[Tralfaz]

Hi there,

 

I am rendering a scene for an animation, and am having a rectangular artifact appear in the final image. The animation is being rendered out at a multipass of 16 (4 x 4). The artifact does not appear until the 12th pass of the image. I am using A:M 13.0n on Windows XP Pro SP2. I have an ATI Radeon 9000 Pro video card and have all the latest drivers for the card and Windows. Out of 150 images rendered, 14 of them have the artifact in the same location and same height, but vary in width. Sometimes the frames affected are sequential, other times they are not. For instance, the frames affected are 16, 17, 18, 19, 20, 21, 22 then skips to 27, 28 then skips to 30, 31, 32 then skips to 34 and finally 39. Frames are being rendered out to .bmp format.

 

Any ideas or suggestions would be appreciated.

 

Thanks...

Al

 

[Edit]

I just rendered to a .tga file and the same thing happens. As soon as pass 12 starts, the solid black rectangle appears.

[/Edit]

 

Frame 15 without artifact

 

Frame 16 with artifact

[Luuk Steitner]

Did you send a bug report yet? Lots of A:M users including me are having this problem. It can be caused by many things. You can try to get rid of the artifact by experimenting with material settings like bump and reflection. Sometimes that helps.

[C-grid]

Tralfaz,

 

- Did you check normals

- Did you try changing the order of decals(if applicable)

- Is something like decalling the spot with a transparant.tga a work-around?

- Did you try a different format(extension) for the decals used?

- Would changing the resolution of the decals used get rid of the problem?

- If you used old-style bump, did you try new-style bump or vice-verca, changing bump-approach to displacement may be a workaround.

- Did you try to use a real low magnitude percentage instead of peak?

- A work-around can be adding a spline if the plancks are separate meshes.

 

It would probably help to tell something about the model and texturing.

Even when you do get rid of it, send in a report anyway.

 

Niels

 

ps.

The time I dealt with it, is some time ago, and I had 'perfect' black-squares...

 

ps2.

When time is a problem use photoshop

[MMZ_TimeLord]

Easy way to test whether it's decals or not is to turn off decals in your final render and leave everything else alone.

 

If it's decals, then your solution could be as simple as re-decaling or reordering way you stamp the model.

 

Good luck!

[Tralfaz]

Thanks for the tips folks.

 

Did you send a bug report yet? Lots of A:M users including me are having this problem. It can be caused by many things. You can try to get rid of the artifact by experimenting with material settings like bump and reflection. Sometimes that helps.

I have not sent in a bug report yet, wasn't sure if it was something I was doing or not.

 

Tralfaz,

 

- Did you check normals

- Did you try changing the order of decals(if applicable)

- Is something like decalling the spot with a transparant.tga a work-around?

- Did you try a different format(extension) for the decals used?

- Would changing the resolution of the decals used get rid of the problem?

- If you used old-style bump, did you try new-style bump or vice-verca, changing bump-approach to displacement may be a workaround.

- Did you try to use a real low magnitude percentage instead of peak?

- A work-around can be adding a spline if the plancks are separate meshes.

 

It would probably help to tell something about the model and texturing.

Even when you do get rid of it, send in a report anyway.

 

Niels

 

ps.

The time I dealt with it, is some time ago, and I had 'perfect' black-squares...

 

ps2.

When time is a problem use photoshop

 

1) Did not check normals

2) There is only one decal applied to the floor.

3) Not sure what you mean about a decaling the spot. The black spot does not appear until the 12th pass of the render on the specific frame.

4) Yes, I tried rendering to a .tga file and the same thing happens.

5) Have not tried changing the resolution of the decal. The image is in .jpg format and is 512 x 512 pixels, 96 dpi horizontal and vertical resolution and 24 bit.

6) No bump maps were used.

7) Not sure what you mean about low magnitude percentage, just went with default values when the decal was applied, other than having it repeat itself to cover the floor properly.

8) The planks are not separate meshes.

 

The floor is essentially a 4 point mesh (created using the 'perfect' mesh techinque) with a single decal applied to simulate the floor surface.

 

I ended up going through the frames that were affected with Photoshop Elements and manually removed the marks.

 

Easy way to test whether it's decals or not is to turn off decals in your final render and leave everything else alone.

 

If it's decals, then your solution could be as simple as re-decaling or reordering way you stamp the model.

 

Good luck!

 

How do you go about turning off the decals in the final render?

 

Things I've Tried:

1) When I render without multipass, the mark does not appear.

2) Rendering multipass (9 3 x 3), the mark does not appear.

3) Turned off all objects except for the one containing the floor, and the mark does not appear in multipass (16 4 x 4).

4) Turned off only the dog, still multipass (16 4 x 4), the mark does not appear.

5) Turned back on the dog, turn off reflections, multipass (16 4 x 4), the mark does not appear.

 

It would appear to be a combination of the dog and reflections that is causing the problem.

 

Al

[C-grid]

I ment something else with 'point 4'...

 

Although the artefacts don't appear in the corner, I strongly suspect "perfect-square mesh techinque" is causing the trouble.

I think the creation of patches through weird broken splines make the renderengine mix-up and not returning the calculated square.

 

Niels

 

ps.

Of course in combination with camera and light-angle (and maybe the actual bumpmap-pixel-color).