Clipping Bug when in Parallel Projection

Hi,

I’ve come across a replicable bug to do with the parallel projection camera setting. Sometimes when using parallel projection some portion of the bottom of the screen will be “clipped” i.e. won’t show.

I just realised that this happens when you are initially in perspective camera mode and zoomed in very close, and then change to parallel projection.

It seems that the parallel mode is using the ‘closeness’ information from where the perspective mode was left. So even when you zoom very far out in parallel mode it still clips the section that would be clipped in perspective.

Zooming in perspective mode moves the camera location.
Zooming (with the ‘Zoom’ tool) in parallel mode enlarges what you see on screen, the camera stays in place.

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Parallel Projection is prone to Camera Clipping.
Its primary purpose is for achieving orthogonal views while Perspective is used for modeling.
Generally, narrowing the FOV in perspective helps alleviate clipping.

See these learning resources:

Clipping — SketchUp Help
https://help.sketchup.com/en/sketchup/clipping-and-missing-faces


Clipping — SketchUp Sage Site

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We’ve had very long discussions about this, and I found that doing a zoom extents fixes most cases. Can you try that, and then only zoom in again after you are in parallel projection.

Yes, zooming out in the perspective mode does indeed fix the issue. Maybe I should have been clearer in the original post that I knew/know how to fix it, I just thought it was worth flagging up as a bug, something that the developers may want to look into fixing.

I would say this specific type of clipping is logical and expected. If you are inside a building in perspective and swap to parallel projection you still expect the camera to be inside of the model. This means everything behind the camera will stay hidden.

The clipping in perspective is a different thing as it hides things that are in front of the camera and logically should be visible.

Btw, if you want to get rid of the clipping in parallel projection, I made a plugin for that.

https://extensions.sketchup.com/extension/04bba8a8-4d06-4d5c-9995-bfe047595f69/eneroth-unclip-parallel