[Chimera-users] Normal recalculation

Elaine Meng meng at cgl.ucsf.edu
Thu Jul 2 09:32:47 PDT 2009

Dear Damien,
In Chimera version 1.4 (daily builds) there is a quality option in the  
Lighting tool (under Tools... Viewing Controls).  Depending on your  
machine, you may be able to set the "quality" to "glossy" -- this will  
make surfaces of all kinds look much smoother without increasing the  
number of triangles.  My knowledge of how it works is a little fuzzy,  
but I thought it somehow uses different normals all over the surface  
instead of just one normal for each triangle.  The "glossy" option  
also turns on angle-dependent transparency.

Glossy lighting was discussed in a little more detail in these recent  

If the main reason for your question is wanting to make the surfaces  
look better, glossy lighting should suffice... as long as you can use  
a computer on which it is available.  I don't know anything about  
getting the normal information out of Chimera (and the person who  
implemented glossy lighting is on vacation right now).
I hope this helps,
Elaine C. Meng, Ph.D.
UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab
Department of Pharmaceutical Chemistry
University of California, San Francisco

On Jul 2, 2009, at 3:20 AM, Damien Larivière wrote:

> Dear Chimera team,
> I have open in Chimera a VRML file containing multiple copies of the  
> FtsZ protein.
> The VRML file does not contain the smooth groups so that, at  
> display, triangles appear at the surface of the proteins as shown in  
> the attached image.
> I would like to get the surface smooth but not by increasing the  
> number of triangles.
> Is there a way in Chimera to recalculate the normals as it can be  
> done in 3DSMax for instance?
> My best regards,
> Damien

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