0
$\begingroup$

I want to render a scene that is containing both regular 3D objects as well as planes containing pictures that are implemented using textures (think of a virtual screen in a virtual scene that is playing some video).

Formally, the size of the plane is calculated pixel-precise. That is, the texture on the plane is passed to the rendered output 1:1 without any interpolation or whatsoever. I did also set the interpolation mode of the texture to "closest" - just to ensure there is no interpolation. Now, the multiple sampling of the Eevee rendering engine is destroying that precision. The image texture is loosing sharpness, which is not desired here. When I set the sampling to 1, everything is fine.

Unfortunately, the multiple sampling is needed for other objects in the scene - i.e. some texts. So what would be needed here is some way to turn off that multiple sampling for the textured plane. One way to walk around that issue would be a two-way process by rendering the objects where multiple sampling is needed and those where none must be used independently on transparent background, and combine both afterwards with some video editor. However, I want to avoid that, if possible.

Thanks for any hints, Mario

$\endgroup$

1 Answer 1

0
$\begingroup$

Probably not directly an answer to that question, since such selective sampling is probably not possible in Blender as of today. But a suitable work-around:

I'm doing this sort of overlay not with a textured plane any more, but I'm using the compositor and an "Alpha Over" node in order to put the image sequence in place.

However, be warned: There is another pitfall that might lead to distortions even in the compositor. You have to take care about the "evenness" and "oddness" of the resolution of the rendered/total image size and the overlaid image size. If the total image size resolution is even (say 100 on the X axis), the exact center is directly between two pixels (e.g. between pixel index #49 and #50). Now, consider the overlaid image resolution is odd (say 25 on the X axis). The center is not between two pixels here, but is falling on a certain pixel - here index #12. In case the overlaid image is centered over the total image size, the pixel #12 of the overlaid image is falling half on pixel #49 of the total image and half on pixel #50. Of course, this is leading to distortions then. To deal with that, one has to either match evenness and oddness of the involved resolutions or by additionally offsetting the overlaid image by +/-0.5 in order to compensate for that shift.

$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .