Also… To illustrate a bit this vertical shift/tilt I made the following screenshots:
Initial camera with camera and target on same height.
This often causes the issue that we see too much ground and not enough sky/building/… to correct this you would look up…
Just looking up will look like this:
As you can see this causes the vertical lines to converge, it’s natural but not always what you want in your composition, therefore there are (in reality as well) vertical tilt and shift (not sure this exists in reality, but tilt lenses do) lenses.
Using such a vertical tilt lens will correct this by tilting the projection plane of the camera lens (if I fully understand it, more in detail on this here)
You can control this vertical tilt with a value, but usually it’s just wanted to get those vertical lines straight again, this can easily be done by using the “auto vertical tilt correction” (or the camera.applyVerticalCorrection() in BJS).
This will skew your view a little bit, but when not exaggerated it’s not a problem.
This will result in this view:
In 3ds Max:
When unchecking the “auto vertical tilt correction” you get to see the number with which the image is tilted. And this number is controllable. That would also be a necessary option in BJS, so that when we animate a camera transition we can let this number transition to match from the first camera to the next
At the moment I did this in the following way:
const updateTilt = setInterval(() => {
cam.applyVerticalCorrection()
}, 5)
An alternative to this however is the vertical shift
Here we would start again with the same view, looking straight forward:
But instead of looking up and correcting with vertical tilt we would be using the vertical shift
What this does is like taking a virtual snapshot of the view but this extends beyond the viewport-boundaries and shifts, or pans this view up-down or left-right, like so:
What’s interesting about this method is that we can also use the horizontal shift, to choose our perspective center-point, but still shift the view a bit left or right if there’s something important that needs to be in view:
Here you can see the center of the perspective (circle) vs the center of the composition/image (cross)
So we would really appreciate to be able to control both the vertical shift (horizontal & vertical) and the vertical tilt (horizontal & vertical). And this with an automatic vertical tilt, but still controllable with a number so we can tween this tilt between camera positions.
Seconday it would be awesome if we could also control the lens shift (horizontal & vertical), just with a number (auto is not needed/possible (?) here).
Thanks a lot!
Pieter