Shadows' trick?

Edson

i did not quite understand your doubt but did you know you can set a group not to cast shadows? (bottom of the shadows dialogue box)

Gaieus

Pilou,

Please, rephrase the question, please. I have read it several times but still unable to understand it and I haven't been wiser from either Panga's or Edson's anwers.

do you want to see the shadows or not
do you want to see that object or not
do you want straight SU output or some rendering (as you referred to)?

pilou

@Gaieus

do you want to see the shadows or not : I want see all shadows (even the shadow's beam
- do you want to see that object or not : I want see the walls, I don't want see the beam
- do you want straight SU output or some rendering (as you referred to)? both : Su and rendering

@unknownuser said:

The advice given was to draw the shadow with faces

@ Panga: Yes but ...some painful

The render tips with a Section plan + camera out this cut will be terrific but seems Podium or Twilight don't make it or I miss something

Anssi

Hi Pilou

Is this what you are trying to do?

Anssi
pilou_box.skp

Gaieus

Yeah, the reason why asked is probebly(???) in Anssi's example.

(I have not opened it just trying to play a game - he probably made it with a totally - 100% - transparent png image file).

Anyway, png transparency (its shadow, more exactly) is not transparent only in SU (or at least, most modern rendering engines would render it transparent).

So while you can take advantage of a SU "bug" (?) - say a limited feature -, when it comes to real lighting, it may become different.

pilou

@Anssi
Yes Exactly! Works fine in Su
How do you make this? (Enable Cast Shadows, Receive Shadows), Special color, Special texture?
(If it's not a magician's secret)
Ah yes I edit the texture so a transparent texture as Gaieus said

Works not in rendering

Ecuadorian

Ok, I'm cheating here...

cheat-box.skp

Anssi

Pilou,

Gaieus was right, of course. I was waiting for you to discover the trick yourself...

Turn on Hidden geometry so you see the beam is there. So as Gaieus said, I painted the beam faces with a 100% transparent PNG texture and hid the lines. You can see the texture in the In Model materials.

How to render this depends on the capabilities of your render application. I would guess that it is not possible with most of them to create an invisible material that casts shadows. In 3D Studio Max, maybe?

Anssi