topic Re: How to eliminate light effect through the wall in Visualization

How to eliminate light effect through the wall

Anonymous — Thu, 11 May 2023 10:37:24 GMT

I use ArchiCAD 9, my problem is when I put a general light source in the room separated by the wall, then when I render the light effect can pass through the wall and luminate another room.

Light source from left area

Light effect through the right area

How can I restrict the light so it can't effect to other room? Please help me, thank you very much!

Re: How to eliminate light effect through the wall

Anonymous — Sat, 11 Jun 2005 11:39:48 GMT

After trying to change any setting then I come with this solution;
Go to Image > PhotoRendering Setting > LightWorks Effects > Shadow Casting then turn on the "HARD" radio button on. If I use "BY LAMP SETTING" the result light effected to other room.

Then the result is

Re: How to eliminate light effect through the wall

Dwight — Sun, 12 Jun 2005 16:02:52 GMT

But that is a bad solution because in a real scene, having an overall shadow casting control of "hard" will affect all the lights, making the scene harsh. A better solution is to use a proper shadow casting light like the wall light indirect - the most sophisticated of the ArchiCAD/LightWorks lamps.

Re: How to eliminate light effect through the wall

Anonymous — Sun, 12 Jun 2005 17:47:20 GMT

Dwight wrote:
But that is a bad solution because in a real scene, having an overall shadow casting control of "hard" will affect all the lights, making the scene harsh. A better solution is to use a proper shadow casting light like the wall light indirect - the most sophisticated of the ArchiCAD/LightWorks lamps.

Dwight, thanks a lot for your reply

I will try your solution then, trully I didn't compare between using "hard" mode and "BY LAMP SETTING" so I will compare it later. But how come this problem happen? Is this a bug from the light source, because I try another light source from Archibase and the result is same, the light effected another room......

Re: How to eliminate light effect through the wall

Dwight — Sun, 12 Jun 2005 17:59:40 GMT

General light sources don't cast shadows because they are omnidirectional - and the math to caculate shadows from an imnidirectional source results in INFINITY. Imagine how long a rendering would take, then!

You need to overlap lights with medium fall off to emulate a general light that casts shadows, but thinking like a photographer, using the three photo light types: key, model and fill, is a better approach.

Re: How to eliminate light effect through the wall

stefan — Mon, 13 Jun 2005 07:01:08 GMT

Dwight wrote:
General light sources don't cast shadows because they are omnidirectional - and the math to caculate shadows from an imnidirectional source results in INFINITY. Imagine how long a rendering would take, then!

Most 3D software solves this by rendering an omni light as if it where six spotlights, so the shadow casting calculation is back to normal.
Cinema4D even manages to calculate transparancy in the shadows even for soft shadows (using shadow maps instead of raytracing).

ArchiCAD lightsources never had much control built in... So to be abel to exploit LightWorks capabilities, do not use default ArchiCAD light sources, since they lack parameters. Even if you would script the light in GDL, the native ArchiCAD-engine misses control over the light.

Re: How to eliminate light effect through the wall

Anonymous — Tue, 14 Jun 2005 07:54:03 GMT

Whoaa man, you too make my head spinning .....maybe my skill is too low to understand. But I'm very very thankful with you Dwight & Stefan, I'll try to understand and do what you suggest.....

Or maybe I can get an easier answer/solution from you too?

Re: How to eliminate light effect through the wall

Dwight — Tue, 14 Jun 2005 13:32:44 GMT

Simpler:

general light that casts shadoze = light cone down and light cone up at 160 degrees aimed at each other about 1.5 meter apart. sort of.

where did you find the fawning berry?

Re: How to eliminate light effect through the wall

Anonymous — Wed, 15 Jun 2005 06:47:14 GMT

Dwight, yes it works well. Even the light not so nice but it's much better now. Very nice of you, thank you!

where did you find the fawning berry?