Texture mapping different in viewport and render view

I work for a while on a project with textures and retrieving the right texture color on an specific position.

I struggled with the UVW rotation in the mapping, because i got another color than i saw in the rendering viewport.
Then i started the render preview and i was a little bit confused, because it looked like this:

If i play with UVW offset or UVW repeat there is no difference between rendered viewport and render preview.
But if i change the UVW rotation it looks totally different.

For me it seems like a bug in the viewport rendering?

P.S.: i just tested the same issue in @serengeti and it behaves also wrong. :sob:

I’m not seeing this here in the v6 WIP… Can you post your file making sure the texture is embedded? This will happen automatically in the WIP.

spheretest.3dm (359.1 KB)

sorry @BrianJ, same bug as in Rhino 5:

it occurs if you use a bitmap texture. Please try my texture …
GetTextureTest.3dm (295.1 KB)

Thanks, filed as http://mcneel.myjetbrains.com/youtrack/issue/RH-34958

In the meantime, I found that in v5 if you switch the mapping channel to 0 in the texture settings it fixes the issue.

Thank you @BrianJ, but i do not understand what do you mean with “channel 0”? If i want to change the channel number it says only numbers above 0 are allowed!?

Another question for Rhino 5: would it be possible to get also an fix in an SR of Rhino 5 for this issue? Because at the moment there are no release plans on your side for Rhino 6 and after release it takes approximately one year on our side to update everything. And we need this functionality at the end of the year :scream:

Apologies on the delay in getting back to you on this… here’s the spot in the texture’s mapping settings where selecting channel 0 fixes the issue here.

Sorry @BrianJ to be a little bit dogged.

I have tested it with mapping channel 0 and now the viewport is the same as the rendering.
But as you may know, i want to retrieve the texture color information with a program code which i got from @andy here get texture color from brep

I made a program which generates small spheres with the color of the texture on the surface. First i tested it with mapping channel = 1 and as you can see in the screenshot the texture in the viewport does not match with the spheres but it does in the rendering:

Now i changed the mapping channel = 0 and it has two changes:

  1. the viewport did not change but the new generated spheres seems to get also another texture
  2. now the viewport and the rendering match but the spheres neither match in viewport nor in the rendering

So i’m not sure if it is a workaround or an even worse bug in the viewport rendering!?

BTW: what means mapping channel = 0? because i cannot generate a mapping channel with the id=0, it says it must be between 1-99999. So it should not be possible to choose mapping channel = 0 in the material, isn’t it?