Hello,

Depending on the viewing angle, sometimes white lines are visible (see arrows) :

With interior only :



On a UV remap view, you see that there is no white in the texture :


It's seems to me that these white lines should not be displayed, whatever the viewing angle.

This message has been edited. Last edited by: Amabilis Support,

I can't say for certain, but it is very likely related to how textures are "sampled" when they are rendered. Usually you have to have a little bit more blue or whatever color you are using beyond the boundaries of what you actually want because the calculations can result in a pixel being sampled that you wouldn't have expected.

quote:

Originally posted by Amabilis Support:
Usually you have to have a little bit more blue or whatever color you are using beyond the boundaries

It may not be very visible on the last image, but the image used for texturing stretches beyond the crop limits.
So there are some colors beyond the boundaries.

That's why I don't undestand why some white lines are visible.

You can also get this effect depending on how the faces are extruded.
If you download and unzip the attached 3DC file.....
This was a single face, divided and then extruded with 'Extrude using face direction' checked.
If you navigate to the rear of the cube you can see the edges of the internal faces on the cube surface...these show up as light coloured lines on the cube surface.
If you apply a white colour to the internal faces they show up as white lines.

They are also visible on the cube sides to some extent depending on the lights and camera angle.

Could this be the problem.

Bazza

Lines.zip (17 Kb, 9 downloads)

Thanks Bazza.

The problem is not with internal faces : there are none.

This is the original model and texture.



I moved the 2 texture cropping areas which are on each side of the line at the left of the 204 sign (there are farther from the edge of the texture image; you can see the x coordinate changes).



Now the white line is not visible anymore.

So the problem is with texturing.

On the orginal model, there is a margin from the edge of the image (for example x=0.004 not 0.000).

I feel that there should be no white line and that the texturing could be improved in 3DC.

This message has been edited. Last edited by: DOM107,

I'll have to think about it some more. I THINK this is what I described previously, but I'm not absolutely certain. I would be curious to see what would happend if you painted in the black area to the LEFT on the texture.

Bazza,

if you choose "extrude as region" this problem goes away. Or perhaps you were just showing this as an example. Though it may be a good example since it is possible that the points in the DOM107's model are not exactly linked together. I'd have to see the model to be sure (I think I've said that before :-))

Yes,it was just an example, thought this may be the problem.
I don't get this happening much in 3DC although it can be a problem when the file is exported to other apps. Especially if the texture is mipmapped.
As the camera moves away from the object and the mipmapping kicks in you can get a kind of 'bleed' from the surrounding areas.
As you say the answere is to extend the area you want to crop then crop well inside this, 2 or 3 pixels should work.
The only way to test this I think would be to re-do the texure under another name, giving each of the areas you want to crop say 3 0r 4 extra pixels. Then as a test apply it to a clone/copy of the original model.

Bazza

DOM107,

I received your model. Thanks for sending it. It was really helpful. I found two bugs in 6.6.5.0 that were quite significant.

The "white line" issue turned out to be quite interesting.

I rendered your image in a couple of different programs and found completely contrasting results. One rendered it better than 3D Canvas and one worse. Here's the "worse" example:



I think I may know how to improve rendering so white lines are minimized. Unfortunately, it will come at a cost. Modelling will become slower and the maximum number of faces/points per object will have to be reduced. I'll have to think about what is most important.

Fixing one of the bugs I found helped with some of your unusual texturing. But, I tried rendering the serious "problem" in the two other programs. In one it rendered things properly, and in one it produced the same result as in 3D Canvas. Interesting again.

This message has been edited. Last edited by: Amabilis Support,

The mystery gets deeper. I managed to get 3D Canvas to render things properly (though still with white lines) by "unlinking" faces using the "Unlink" operation. I'm going to look at this more closely.

This message has been edited. Last edited by: Amabilis Support,

Looks to me like the border colour is leaking into the texture from the texture filtering.

Are you using SetTextureStageState 0, D3DTSS_ADDRESSU(or V), D3DTADDRESS_BORDER
instead of D3DTADDRESS_CLAMP or D3DTADDRESS_WRAP ?

Thanks Paul. I'll have a look at that for 6.5.5.1 (probably available shortly ;-)).

That wasn't it. I'm using D3DTADDRESS_WRAP (the default).

I still haven't figured this out. There's some funny stuff happening. I wonder if there is some sort of setting for accuracy.

The white lines are gone for 6.6.5.1.

I managed to figure it out finally. It turns out if you use anything other than D3DTEXF_NONE for D3DTSS_MIPFILTER you get poor results.

There's still more to do. I have to think some more about some of the differences between 6.5 and 6.6.5.0 on your model, DOM107

I managed to figure out the cause of the distorted rendering of textures. It was a really interesting problem. One of the most interesting I can remember.

I turns out that it is possible to triangulate a face in such a way as to cause texture distoration. It seems that you can reduce the chances of distortion by merging colinear edges before triangulating. There may also be other ways to reduce distortion. So far in my tests I have no distoration.

Here's a render of your model, DOM107 (I circled the spot that had the most distortion):



So, I am calling this problem resolved.

This message has been edited. Last edited by: Amabilis Support,

Hi,

Thanks for fixing problems quickly !
I'll check 6.6.5.1 as soon as it is available.

The image posted looks OK as far as "white lines " are concerned.

About the "texture distortion", it was not present in 6.5. If this happens again, I take note of the hint (merging colinear edges before triangulating).

You're welcome. Just trimming a point can be enough sometimes. But, 6.6.5.1 internally removes colinear edges before rendering so it really isn't necessary in 6.6.5.1

I've attached an image that shows a case where the changes in 6.6.5.1 do not correct a texturing problem. The solution in this case was simply to create a new edge between points. Sometimes it's enough just to triangulate a face. I think that it causes the triangles to be rendered in a different order and that's all it takes.

I just found something interesting. I was looking back at this model in 6.5.1.0. It turns out there are similar problems, at least on my computer. I'm guessing there is no perfect solution and that manual intervention is occasionally necessary.

Here's a screen capture from 6.5.1.0:



I wonder if it makes a difference what graphics card you use. I would think they use the same methods. But if they re-order faces within the driver for efficiency purposes (which I think they may well do), it could render differently.

Yes, I noticed the same thing on my computer with 6.5.1.0 (ATI radeon X800XL + Catalyst 6.8).

No such problem with 6.6.5.0 which is excellent news !