Thomas de Groot <tho### [at] degrootorg> wrote:
> On 9-11-2017 13:46, clipka wrote:

> >
> > Uh... and what exactly would "not cast shadows" do, if not make the
> > object "transparent to the light [directly from light sources]"?
> >
>
> Well, my thoughts did not go into that direction to tell the truth. Just
> no shadows, without implications.
>

I'm actually with Thomas on this one-- and not just to be argumentative ;-)

In its strictest sense, no_shadow implies only what it says (IMO), because the
object (the wall) is still *visually* OPAGUE. The fact that no_shadow also
allows light to pass *through* the wall-- as if it's invisible to the light--
seems to me to be a 'secondary effect', not necessarily implied by the meaning
of no_shadow-- and might well be an unexpected effect for new users.

When I started my make my test code example, *I* actually didn't realize (or
remember) the 'dual nature' of that keyword, and didn't even try adding it to
the wall as the first step(!). Instead, I went off on a tangent, coming up with
the (unnecessary!) light_group idea first, to figure out a way to get the light
to strike my sphere object through the 'opague' wall! :-0

The documentation says "You may specify the no_shadow keyword in an object to
make that object cast no shadow. This is useful for special effects and for
creating the illusion that a light source actually is visible"-- then it refers
to the looks_light object in a light. The latter part of that sentence might
actually makes little sense to a new user, unless he/she is already familiar
with what a looks_like object is. (But no_shadow is no longer required there
anyway, as a looks_like object already has an implied no_shadow keyword.)

Since both Thomas and I both failed to initially grasp no_shadow's full meaning,
I imagine there may be others as well...

My two cents :-)

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