Rendering a normal map with RADIANCE

Dear All,

is it possible to get RADIANCE to render a normal map, i.e., an image where RGB values are not radiances (or irradiances) buth rather the xyz components of the surface normal at the intersection point (in either view or world coordinates)?

Best,
Claus

There used to be a patch (by Mark Stock?) for Radiance to allow something like that, adding a texpic modifier. What do you need this for? I think it should be possible to convert you 'picture' into a .dat file?

Lars.

It should be possible with rtrace and the -on option.. and driving rtrace with vwrays as described in Axel Jacobs tutorials.. But I'm not expert and I never tried it.

Lucio

.
.
.Dear All,
.
.is it possible to get RADIANCE to render a normal map, i.e., an image
.where RGB values are not radiances (or irradiances) buth rather the xyz
.components of the surface normal at the intersection point (in either
.view or world coordinates)?
.
.Best,
.Claus
.

.. Caminante no hay
camino, solo se hace
camino al andar ..

          --- o
meglio ---

.. Caminante el
destino no es al
final de el viaje,
pero en todo el
andar ..

Hi Lars,

I need it for importing the per-pixel normals into a program I am writing myself, which will estimate the scene illumination conditions from an image of a scene. I have a 3D model of the scene, I know the camera position and orientation relative to the scene, and from the camera I get the "measured reflected radiances". Given the per-pixel normal information I have developed a method for estimating the illumination conditions in the scene ... makes sense?

Best,
Claus

Lars O. Grobe wrote:

···

There used to be a patch (by Mark Stock?) for Radiance to allow something like that, adding a texpic modifier. What do you need this for? I think it should be possible to convert you 'picture' into a .dat file?

Lars.

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Claus hello,

sorry, but I was in a hurry and misunderstood your mail! My answer was for just the opposite way - using an existing image as a normal map in Radiance. For your application, go on with Lucio wrote and just ignore my post! :wink:

Lars.

Claus,

I need it for importing the per-pixel normals into a program I am
writing myself, which will estimate the scene illumination conditions
from an image of a scene. I have a 3D model of the scene, I know the
camera position and orientation relative to the scene, and from the
camera I get the "measured reflected radiances". Given the per-pixel
normal information I have developed a method for estimating the
illumination conditions in the scene ... makes sense?

Well, perhaps if you're going to do something 'fancy' (but no if you just want the illuminance). As suggested, a command like this:

vwrays -ff scene.pic | rtrace -h -w -fff -on scene.oct > norm.dat

will write out a binary file of the normal at intersection for each pixel.

I'll own up to being intrigued. The derivation of the "illumination conditions" at the pixel will be confounded by any deviation that the scene materials have from pure diffuse reflector. In any case, you'll need to know what those diffuse reflectances are on a per pixel basis. Can you expand a little on your method?

-John

···

-----------------------------------------------
Dr. John Mardaljevic
Senior Research Fellow
Institute of Energy and Sustainable Development
De Montfort University
The Gateway
Leicester
LE1 9BH, UK
+44 (0) 116 257 7972
+44 (0) 116 257 7981 (fax)

[email protected]
http://www.iesd.dmu.ac.uk/~jm