Shadows in workbench mode make the scene much slower than in EEVEE render mode

On my somewhat dated GPU, I noticed that if I activate shadows in workbench mode the scene slows down considerably, which is not the case in EEVEE render mode, is it a flaw that only appears on my GPU or is it common?
it happens both on the official blender 2.80 and on the last 2.81 build.

Shadows in workbench are generated in other way more expensive.

so is it a problem that is common to all?

but if in the workbench the preview display speed is priority for editing, what is the purpose?

and why are shadows generated differently?


investigating … it seems that the shadows in the workbench are affected by the problem of the high density mesh bottleneck …
because opening other scenes, even very rich in objects and complexity, the problem does not manifest itself …

Shadows in workbench are similar to a doom3 shadow, it’s more expensive because instead of render a image and project… it project the shadows perfectly. Or something similar. So each polygon is important and high mesh density suffer a lot with that.

The idea is to have a feature that other programs for CAD have, is not really a feature that you must to use if you model with some experience

OK! I got it…
I assume that this slow down will resolve itself when they resolve with high density meshes bottle-neks

i think this is shadow mapping, basically projecting the same geos, so the heavier the scene the slower it gets, there are other techniques that makes it faster.

yes if there are a lots of objects and tiny holes it could be easily slower than the shadows in eevee or devlook

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