Rotating paths between A and B

[Luma3d]

So I'm running into an issue. When I create cams for animation within Vantage ( A and B ) I get the pivot swirl between them. I haven't run into this issue in awhile. I noticed that it happens when I have Vray physical cameras present in the MAX file. Works fine when no cams exist. Using 3ds MAX 2023.3, Vray 6 update1.1 and Vantage 1.84. Any way to fix this issue?

[Luma3d]

Might have figured it out...does lens focal length setting affect this? Once I set it to a normal 20mm settings it started to work.

[npg]

Do you mean the camera does something like a cartwheel or extra spin when interpolating between two points? It's a pretty rare issue that we've seen in the past. I doubt it can be related to the focal length because the position interpolation only uses the camera matrix.

[Luma3d]

Yes...that's what I mean. Any idea why it's happening?

[npg]

It seems something is going wrong with the quaternion interpolation we do. We have a scene that we can reproduce this with (assuming it's the same thing we're talking about). I will raise the priority.

When I tried with our scene the issue disappeared when I saved one of the camera positions slightly rotated. Before that it was perfectly aligned to the world XYZ axis. If possible, try perturbing your camera a bit to see if this can be used as a workaround until we fix the bug.