On 1/3/21 5:36 AM, kurtz le pirate wrote:
> Hello,
> 
> Little brain teaser : the attached image is part of an animation that 
> simulates a simplified sundial. In order not to overload the image, the 
> shadow of the sundial has been removed with the "no_shadow" attribute. 
> But not for the gnomon to get the "time". As you can see, its shadow is 
> also projected on the ground "through" the wall.
> 
> So, how to remove this shadow on the floor but keep the shadow on the 
> wall ?
> 
If the scene is simple - like what you shown - you might be able to dial 
back on the scene's max_trace_level until the unwanted shadow disappears.

There is also the projected_through feature for lights. If you put a 
special object on the back side of the no shadow shape (or maybe just 
the gnomon) for that projection_through shape it should be the shadow 
disappears. Off the top of my head a little unsure about how light 
attenuation (if any) acts with the feature.

Hmm, wonder if you could just project through no shadow shape... Would 
the shadow on it still show up normally?

Might also be seam issues to fight between any inserted 
projected_through shape and the seen ones if that shape is in the scene.

IIRC. You need not otherwise insert a projected through shape in scene. 
Meaning it can be defined and then referenced only by the 
projected_through keyword in the light. In that way it affects nothing 
else in the scene except being a local light portal into the scene for 
the given light definition.

Bill P.

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