plotly / plotly/plotly.py

Mesh3d ignores lighting with orthographic projection

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bug P3
Dominant language
Python
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Description

It seems like lighting of Mesh3d is ignored when orhogonal projection is used, example image:

image

With exactly the same plot, but with perspective projection, lighting is fine:

image

I just wonder if this is a known issue, or is it a bug somewhere?

I tried to play around with camera locations and lighting parameters (diffuse, ambient, etc.).

Only ambient lighting has effect when orthographic projection is enabled (as you can see in the picture above the whole mesh only has a single flat color) - maybe shader issue?

The version of plotly.py that I am using is 5.6.0.

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Research direction

Start by reproducing the Mesh3d example with orthographic and perspective projection in plotly.py 5.6.0, then compare the rendering behavior and investigate the suspected shader path. Done means diffuse and other non-ambient lighting affect the mesh under orthographic projection without regressing perspective rendering.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
data-visualization
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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