View topic - Photon Mapping problem.

Photon Mapping problem.

Post here general questions about usage of YafaRay and about the Blender Exporter UI

Photon Mapping problem.

Post Thu Oct 08, 2009 11:10 pm

Hi,
I have a problem with my scene. Yaf(a)Ray making a photon cloud under the bed and the other objects and I can't clean it... I Already read this tutorial: http://www.pitat450.net/index.php?id=yafaray_guide, but I can solve my problem.
I know about the teory of the photons, but I can apply it in other renders engine!
Depth: 10
Photons: 2.000.000
Diff. radius: 2
Caustic mix: 100
Search: 100
yafaray.jpg
Thanks,
Victor.
victorphellipe
 
Posts: 95
Joined: Sat Jan 10, 2009 9:31 pm
Location: Brazil, Brasilia.

Re: Photon Mapping problem.

Post Fri Oct 09, 2009 7:13 am

Photon mapping requires that thickness in objects is correctly modelled (closed extruded meshes). In this way we avoid estimation problems when searching for neighboring photons.
User avatar
Samo
 
Posts: 3105
Joined: Tue Dec 20, 2005 10:39 am
Location: Spain

Re: Photon Mapping problem.

Post Fri Oct 09, 2009 8:49 pm

I already check my meshes, and they are modelled in the correct way. Can you give me another tip?! :D
Anyway, I'll make some test to try to understand forever the photons in Yaf(a)Ray. Thank you, Samo!
Blender Brasil team - blender.com.br
Portfolio online
victorphellipe
 
Posts: 95
Joined: Sat Jan 10, 2009 9:31 pm
Location: Brazil, Brasilia.

Re: Photon Mapping problem.

Post Fri Oct 09, 2009 9:57 pm

can you post the scene?
User avatar
Samo
 
Posts: 3105
Joined: Tue Dec 20, 2005 10:39 am
Location: Spain

Re: Photon Mapping problem.

Post Sat Oct 10, 2009 1:03 am

all of your objects maybe properly closed, but is the floor? Other than that someone would need to see the blend
loh
 
Posts: 250
Joined: Sat Sep 20, 2008 3:22 am

Re: Photon Mapping problem.

Post Sun Oct 11, 2009 5:46 pm

Of course!
Meu quarto (YaR).rar
(921.37 KiB) Downloaded 287 times


Thanks for help!
Blender Brasil team - blender.com.br
Portfolio online
victorphellipe
 
Posts: 95
Joined: Sat Jan 10, 2009 9:31 pm
Location: Brazil, Brasilia.

Re: Photon Mapping problem.

Post Mon Oct 12, 2009 2:17 am

victorphellipe wrote:Of course!
Meu quarto (YaR).rar


Thanks for help!

extruding the floor down solves the problem :)

"Power tends to corrupt, and absolute power corrupts absolutely. Great men are almost always bad men."

User avatar
condar
 
Posts: 771
Joined: Sun Apr 12, 2009 2:41 am

Re: Photon Mapping problem.

Post Mon Oct 12, 2009 3:12 am

This plane I add just to test if the problem is happening because the "real" floor, in layer 15, but I was wrong. Anyway, extruding the plane not work, the cloud continue. And the cloud is appearing on the wall too, behind the computer, and the wall is extruded.
I already try to increase the size of my scene, but not work... And I don't know if this maybe solve this problem!
:(, will I have to use PathTracing to render it?!

Thanks!
Blender Brasil team - blender.com.br
Portfolio online
victorphellipe
 
Posts: 95
Joined: Sat Jan 10, 2009 9:31 pm
Location: Brazil, Brasilia.

Re: Photon Mapping problem.

Post Mon Oct 12, 2009 4:38 am

victorphellipe wrote:This plane I add just to test if the problem is happening because the "real" floor, in layer 15, but I was wrong. Anyway, extruding the plane not work, the cloud continue. And the cloud is appearing on the wall too, behind the computer, and the wall is extruded.
I already try to increase the size of my scene, but not work... And I don't know if this maybe solve this problem!
:(, will I have to use PathTracing to render it?!

Thanks!

I made a test extruding the floor and rendering with photon Mapping without problems.

"Power tends to corrupt, and absolute power corrupts absolutely. Great men are almost always bad men."

User avatar
condar
 
Posts: 771
Joined: Sun Apr 12, 2009 2:41 am

Re: Photon Mapping problem.

Post Mon Oct 12, 2009 7:21 am

I think what causes the problem here is the combination of the walls/floor/ceiling being too "thin" and the Diffuse Radius being set to a relatively high value.

If I understood the photon mapping tutorial in the documentation correctly, the Diffuse Radius sets the size of a photon in Blender units. So, if your photon size in Blender units is larger than the thickness of your walls in Blender units, light may leak through.

So you could:
a) decrease Diff. Radius,
b) extrude your walls/floor/ceiling more,
c) scale the whole scene up.

A combination of a) and b) worked for me with your scene, just as condar has reported.
IkariShinji
 
Posts: 176
Joined: Tue May 05, 2009 6:57 pm

Re: Photon Mapping problem.

Post Mon Oct 12, 2009 1:06 pm

Thanks Iraki, I understood your explanation very well. Problems like this will not happen anymore, I wish! :lol:
IkariShinji wrote:if your photon size in Blender units is larger than the thickness of your walls in Blender units, light may leak through.
That is the problem, I always modeled my scenes considering than 1 meter would be equal to 1 Blender Unit.
Some clouds disappear, but I extruded the floor/wall a lot! I did not know I needed to extrude like this. But a cloud still continue in the object under the computer... And others clouds appearing. Now I'm doing test with size, Diff. Radius and Caustic mix.
Look, decreasing the Diff. Radius the noise seems to multiply... If I increase the Photon number maybe I can reduce the noise?

Thanks!
Blender Brasil team - blender.com.br
Portfolio online
victorphellipe
 
Posts: 95
Joined: Sat Jan 10, 2009 9:31 pm
Location: Brazil, Brasilia.

Re: Photon Mapping problem.

Post Mon Oct 12, 2009 2:34 pm

Here's my result with your scene:
Meu quarto.png
Render Result

And here are the corresponding render settings:
Render Settings.jpg
Render Settings

Had to thicken the walls quite a bit, though: I have to admit they are now a little bit out of proportion (about 0.4 Blender units thick). I guess the Diff. Radius has to be even lower than the 0.250 I used to keep the wall thickness proportional to the scene size.
IkariShinji
 
Posts: 176
Joined: Tue May 05, 2009 6:57 pm


Return to General Questions and Blender Exporter UI



Who is online

Users browsing this forum: No registered users and 3 guests

cron