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[Closed] Define camera frustum corners ?

Hi,

Ideally I would like to be able to modify the camera frustum by specifying the 4 corners precisely, but I don’t even know if that’s possible. I added a picture to illustrate what I’d like to achieve. The 4 corners are circled in red, and the wanted frustum is purple.

Can someone point me in the right direction about this?

Edit: I tried with the physical camera horizontal/vertical shift and even though I managed to set up the cone correctly in the viewport, when switching to camera view it’s totally different and doesn’t match the cone at all…

Thanks in advance!

4 Replies

There is a bug on the physical camera with shift meaning what you see through the viewport isn’t always what renders.

The other thing you can try doing is add two Skew Modifiers to the camera and play with the X/Y until you get your match.

Thanks! I’ll try the skew modifier. And you are right about the wrong shifted view in the viewport, it’s correct when rendering.

Any idea if setting the 4 corners of the camera frustum with maxscript is doable ?

If you’re looking for an easy way to access and modify corners of the frustum – nope, there isn’t one.
The closest thing you can do is add an FFD modifier to the camera, but that wouldn’t allow you to move the corners independently, its deformations would be similar to skewing and scaling the camera.

Controlling the corners independently is possible in principle, but probably not in 3ds max.
Usually you’re limited to how you can deform a matrix in 3ds max: skewing and nonuniform scaling are about the nastiest things you can do with a matrix here and they’re still affine transformations. To deform corners independently you’d need to expand/contract opposite sides of frustum different amounts, for which you’d need to make a projection matrix, which is not affine. Afaik, 3ds max doesn’t allow you to do anything with the 4th column of a matrix, so making a projection matrix is likely impossible.

Thanks for the clarification !