HELP ME WITH THIS PROBLEM

August 12th, 2002

PLEASE can someone tell me why VIZ4 doesn't give the specular on the material it is my error?
I tried with radiosity ovverride material but nothing

PALMIRO or something else please help me

Bye from Stefano

nisus · August 12th, 2002

Hi stefano,

What do you mean exactly? Are you using standard or *RT materials?

rgds

nisus

*RT: raytraced

August 13th, 2002

Hi Nisus
I mean the normal specular highlight on an object like in scanline render.
I used the standard material but there is no specular on the objects

If you know this problem please help me
Bye
Stefano

plastic · August 13th, 2002

you can use an omni light that only affects specularity, to simulate it when using GI.
remember that the max specular highlights are no physically correct approach. radiosity simulates real-world lighting. to get real specular reflections/highlights you have to use raytracing and very bright object-lights or hdr-images.

read this article:
http://www.neilblevins.com/cg_educat...l_and_refs.htm

nisus · August 13th, 2002

Hi stefano,

I need more information on your file. Did you check the highlight button in the sun settings?
What shader are you using? ...

Can you post your file?

rgds

nisus

August 13th, 2002

Hey NIsus thanks for the reply
I could send an image sample but I don't know a site where to send it
If you know where and how please tell me
I need help
I must produce work for a portfolio
BYe from Stefano
ITALIA

August 31st, 2002

Is it possible that a programm like VIZ4 after you have calculated the radiosity and launch the render give the material without specular highlights.
Noone can tell me where I'm wrong (I hope I'm wrong)I can't believe that it's a bug to solve with additional lights (with only specular).
Please help me

abicalho · September 1st, 2002

This is really a tricky issue.

Why? Well, let's think of how the renderer happens before you have Radiosity. You have a lot of specularity, because you have a very well defined light source.

When you add Radiosity, what happens to the light? It bounces back and forth, and the light now will not come from a single light source, but instead it comes from "everywhere".

This will make your specular highlight fade and in some cases almost disappear in the scene.

The trick to solve it is to add "Specular-Only" light sources, so you can control specular highlights manually.

Alexander | discreet Quality Engineer

September 1st, 2002

THank you abicalho for the reply
Now I can be sure that I must add light with only specular on to solve the problem.
Thank you very much
I appreciate
Can I ask you why in some cases the light come in to the room inside the corners? (the room s modeled with box primitive and inverse normal)If I put the meshing 0.20 (unit in meters)it gives the same problem .Must I reduce the meshing parameters to 0.05?

Excuse me for the second question.
But you are of the DISCREET GRoUP, who better than you can give me some suggests?

THANK YOU

plastic · September 2nd, 2002

>>the room s modeled with box primitive and inverse normal

don't do this. there are no 2-dimensional walls. model the room in a physically correct way.

August 12th, 2002	#2 (permalink)
nisus Super Moderator Join Date: Mar 2002 Location: Gent Flanders Belgium Europe Age: 32 Posts: 3,276 Name: Evert Vandenberghe	Hi stefano, What do you mean exactly? Are you using standard or RT materials? rgds nisus RT: raytraced __________________ www.ams.be / www.nisusarts.com http://www.youtube.com/profile_videos?user=nisusCGA&p=r

August 13th, 2002	#4 (permalink)
plastic Senior Member Join Date: May 2002 Location: vienna, EU Posts: 314 Name: Marc Lorenz	you can use an omni light that only affects specularity, to simulate it when using GI. remember that the max specular highlights are no physically correct approach. radiosity simulates real-world lighting. to get real specular reflections/highlights you have to use raytracing and very bright object-lights or hdr-images. read this article: http://www.neilblevins.com/cg_educat...l_and_refs.htm __________________ Marc Lorenz http://plugins.angstraum.at My 3d gallery at Flickr

August 13th, 2002	#5 (permalink)
nisus Super Moderator Join Date: Mar 2002 Location: Gent Flanders Belgium Europe Age: 32 Posts: 3,276 Name: Evert Vandenberghe	Hi stefano, I need more information on your file. Did you check the highlight button in the sun settings? What shader are you using? ... Can you post your file? rgds nisus __________________ www.ams.be / www.nisusarts.com http://www.youtube.com/profile_videos?user=nisusCGA&p=r

September 1st, 2002	#8 (permalink)
abicalho Veteran Member Join Date: Dec 2001 Location: San Francisco Age: 35 Posts: 643 Name: Alex Bicalho	This is really a tricky issue. Why? Well, let's think of how the renderer happens before you have Radiosity. You have a lot of specularity, because you have a very well defined light source. When you add Radiosity, what happens to the light? It bounces back and forth, and the light now will not come from a single light source, but instead it comes from "everywhere". This will make your specular highlight fade and in some cases almost disappear in the scene. The trick to solve it is to add "Specular-Only" light sources, so you can control specular highlights manually. Alexander \| discreet Quality Engineer __________________ Alex Bicalho http://www.origamy.com.br/blog

September 2nd, 2002	#10 (permalink)
plastic Senior Member Join Date: May 2002 Location: vienna, EU Posts: 314 Name: Marc Lorenz	>>the room s modeled with box primitive and inverse normal don't do this. there are no 2-dimensional walls. model the room in a physically correct way. __________________ Marc Lorenz http://plugins.angstraum.at My 3d gallery at Flickr

August 12th, 2002	#1 (permalink)
penguin71 Guest Posts: n/a Name:	PLEASE can someone tell me why VIZ4 doesn't give the specular on the material it is my error? I tried with radiosity ovverride material but nothing PALMIRO or something else please help me Bye from Stefano

August 13th, 2002	#3 (permalink)
penguin71 Guest Posts: n/a Name:	Hi Nisus I mean the normal specular highlight on an object like in scanline render. I used the standard material but there is no specular on the objects If you know this problem please help me Bye Stefano

August 13th, 2002	#6 (permalink)
penguin71 Guest Posts: n/a Name:	Hey NIsus thanks for the reply I could send an image sample but I don't know a site where to send it If you know where and how please tell me I need help I must produce work for a portfolio BYe from Stefano ITALIA

August 31st, 2002	#7 (permalink)
penguin71 Guest Posts: n/a Name:	Is it possible that a programm like VIZ4 after you have calculated the radiosity and launch the render give the material without specular highlights. Noone can tell me where I'm wrong (I hope I'm wrong)I can't believe that it's a bug to solve with additional lights (with only specular). Please help me

September 1st, 2002	#9 (permalink)
penguin71 Guest Posts: n/a Name:	THank you abicalho for the reply Now I can be sure that I must add light with only specular on to solve the problem. Thank you very much I appreciate Can I ask you why in some cases the light come in to the room inside the corners? (the room s modeled with box primitive and inverse normal)If I put the meshing 0.20 (unit in meters)it gives the same problem .Must I reduce the meshing parameters to 0.05? Excuse me for the second question. But you are of the DISCREET GRoUP, who better than you can give me some suggests? THANK YOU

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