# lighting per pixel or per face?

Hi there!

I am wondering whether radiance make per pixel computations for lighting or it just make computations per face (triangle/surface)

I have tried to illuminate a cylinder with a light probe.
If you look at resulted image, you can distinguish the faces/divisions from which cylinder model is made of.

You can see the result in jpg here
The problem that I tried to explain in the previous paragraph is there where red arrows show. (I added arrows manually)

Is there a way to make the lighting smoother in area where red arrows show?

I used this to take the result:
rpict -x 600 -y 600 -t 30 -ab 2 -ar 10000 -aa 1.0 -ad 2048 -as 1024 -st 0 -sj 1 -lw 0 -lr 8 -vf camera.vp thermos12_base.oct > res.hdr

Thanks,
Despina

Is that an imported/converted cylinder or a native Radiance cylinder?
If the former, try increasing the poly resolution before exporting
I use obj2mesh and it smooths pretty well

I believe its per pixel computation

Rob F

···

-----Original Message-----
From: Despina Michael
Sent: 3/23/2005 1:45 PM
Subject: [Radiance-general] lighting per pixel or per face?

Hi there!

I am wondering whether radiance make per pixel computations for lighting
or it just make computations per face (triangle/surface)

I have tried to illuminate a cylinder with a light probe.
If you look at resulted image, you can distinguish the faces/divisions
from which cylinder model is made of.

You can see the result in jpg here
The problem that I tried to explain in the previous paragraph is there
where red arrows show. (I added arrows manually)

Is there a way to make the lighting smoother in area where red arrows
show?

I used this to take the result:
rpict -x 600 -y 600 -t 30 -ab 2 -ar 10000 -aa 1.0 -ad 2048 -as 1024 -st
0 -sj 1 -lw 0 -lr 8 -vf camera.vp thermos12_base.oct > res.hdr

Thanks,
Despina
<<ATT1462924.txt>>

Hi,

You probably need to figure out how to export your polygonal geometry in a format such as .obj or .3ds which can be converted into Radiance with smoothing. Alternatively, you could construct the object in Radiance using the built in cylinder and ring geometric primitives.

-Jack

Despina Michael wrote:

···

Hi there!
I am wondering whether radiance make per pixel computations for lighting or it just make computations per face (triangle/surface)
I have tried to illuminate a cylinder with a light probe.
If you look at resulted image, you can distinguish the faces/divisions from which cylinder model is made of.
You can see the result in jpg here
The problem that I tried to explain in the previous paragraph is there where red arrows show. (I added arrows manually)
Is there a way to make the lighting smoother in area where red arrows show?
I used this to take the result:
rpict -x 600 -y 600 -t 30 -ab 2 -ar 10000 -aa 1.0 -ad 2048 -as 1024 -st 0 -sj 1 -lw 0 -lr 8 -vf camera.vp thermos12_base.oct > res.hdr
Thanks,
Despina

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Hi,

the model is .obj file and I used obj2rad to convert it in .rad file. Then I
added in .rad material and lighting info and use rpict to illuminate the
object.

It's not a "perfect cylinder" and this is the reason I don't use radiace
primitive cylinder (it just looks like a cylinder)

Can you tell me please how I use obj2mesh command?

I tried this
obj2mesh model.obj > out1.rtm
but it does not seem to work. There is an error: obj2mesh: fatal -
unreferenced uv coordinates

Thanks,
Despina