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I want to be able to make 1 or several meshes at once use the effect of being orthographic in perspective view. For example, a cube looks orthographicaly flat or even while other cubes can look as if they are in perspective. I have not found any way as blender is just basic perspective or orthographic view for the whole scene. Any means, even using nodes of some kind to create this effect would be nice. Another point would be to have an intensity driver and you can blend or morph the mesh invidually between a perspective and orthographic view effect. Also if this is to be done, would the mesh having this effect act weirdly if it is a child or the parent of another mesh or if it has shape keys applied to it. Again, I don't think this effect is in blender natively, which is why I want to ask is there a way to fake it (either with nodes or some code, but I do not know coding as of the moment).

Jessie Ferret
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    Maybe this is useful? https://blender.stackexchange.com/questions/111133/assign-camera-to-renderlayer – taiyo Aug 29 '23 at 06:39
  • Thank you! This is a start. So, a way to do it is to create separate scenes and blend them in the compositer. I also wanted an intensity/ morphing driver between a mesh being orthographic and in perspective. I'm not sure how to go about that.... – Jessie Ferret Aug 29 '23 at 17:53
  • Not sure if that's possible. Afaik see, there is no option to set a custom projection matrix of a camera. – taiyo Aug 29 '23 at 19:47
  • How about some sort of morphing node that mimic the effect while in perspective view, sort of warping the mesh to fake that orthographic look. I recon there would be some math involved, especially to make it look orthographic no matter the camera angle.... – Jessie Ferret Aug 29 '23 at 20:58
  • Had the same thought. Have a look at Shape Keys https://docs.blender.org/manual/en/latest/animation/shape_keys/introduction.html#workflow which let you morph meshes. Given the base shape key for perspective view, you would need to calculate the vertices' orthographic positions from the current camera view and save that in a relative shape key. But well, i think this will be tough. – taiyo Aug 29 '23 at 21:11
  • Thank you, I will look into it. It does look like a lot of work as you said. – Jessie Ferret Aug 29 '23 at 21:50
  • I found this article on wiki. https://simple.wikipedia.org/wiki/Orthographic_projection I don’t know how to set the camera like this in blender though…..If I could get the effect like the gif shown with the cube and do the separate scenes thing, this problem would be solved. – Jessie Ferret Aug 29 '23 at 23:23
  • That's nice! It would be way simpler than calculating fake orthographic morph vertices. – taiyo Aug 29 '23 at 23:50
  • Yes, much more simple. But can blender to the infinity focal length with zero degree angle (whatever that is)? – Jessie Ferret Aug 29 '23 at 23:58
  • I crafted an answer, hope it helps. And well, most programs don't like real infinities due to numerical limits but getting close should be enough. – taiyo Aug 30 '23 at 00:24

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To combine orthographic and perspective shots, see here Assign camera to renderlayer.

For the part asking for an morph between perspective and orthographic view, you can animate some properties based on your finding from your comments. Sorry for the lazy screenshot, but it should show all necessary things. The values are handmade until it looked convincing, surely one can derive formulas for this. You need to animate (from red to green):

  • the Focal length of the camera (to fake infinite focal length)
  • the camera's position (to fake infinite distance)
  • the near (Clip Start) and far (End) plane of the camera's frustum (to keep the z-fighting problems away)

enter image description here

The above setup gives me this result, after frame 50 i can see barely any differences anymore:

enter image description here

taiyo
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