How to switch perspective to orthographic with correct settings

Questions
1

Hi~
I want to add a function to switch camera between perspective and orthographic, I need to correctly set orthoLRTB to keep camera looks like in same position and distance. I have tried this pg (https://playground.babylonjs.com/#QN0D08#1), I am not sure if it’s right.
The current switch is instantaneous. Is there a gradual way to transition from perspective to ortho?

2

Orthographic mode is basically just fov = 0

so what you want is to transition fov from whatever it is right now to 0

but changing fov causes a zooming effect so you also have to move the camera back to keep the frame constant.

But if you actually transition to fov = 0, your camera will need to be at inifinity distance.

so what we actually do is.

  • transition fov to near 0 (say 0.001)
  • then change to ortho view

I asked chatgpt to implement this and it did a pretty good job, here’s the PG

Press “t” to transition

(you’ll prolly need to save some of your initial camera params to do the reverse transition)

3

Thank you! It is pretty good job! :laughing: