[chimerax-users] Displaying silhouette around specific visual elements

[Elaine Meng]

Hi Andre,
Sometimes you can approximately "fake" this effect by using the selection outline.  It is not the same, however, as silhouettes; it will only go around the outside perimeter of the selected item(s).  For example, if I have a molecule inside a map surface, I can make the surface transparent, select the atomic structure, and make the selection outline color black etc. as in these commands, resulting in the appearance in the attached image.

open 2gbp
molmap protein 8
trans 70
view
set bgColor white
select @*
graphics selection color black

I hope this helps,
Elaine
-----
Elaine C. Meng, Ph.D.                       
UCSF Chimera(X) team
Department of Pharmaceutical Chemistry
University of California, San Francisco




> On Mar 25, 2021, at 8:23 PM, Tom Goddard <goddard at sonic.net> wrote:
> 
> Hi Andre,
> 
>  It is not currently possible to display silhouettes on some models and not others.
> 
>  Several people have wanted this but I think it is complex to achieve.  The silhouettes show boundaries where the depth in the entire scene changes abruptly.  In order to have per-model silhouettes the ChimeraX GPU shader programs would need to compute an additional depth buffer separately for each model.  Also the silhouette edges are not currently drawn at a specific depth.  If per-model silhouettes were supported a stick model with silhouettes beneath a transparent surface needs to draw the silhouettes under the transparent surface so knowing the depth of the silhouette edge becomes important.  When not using silhouettes the shader programs need to not compute the extra per-model depth buffers otherwise it would slow down rendering even when not being used.  Adding these additional complexities to already complex graphics rendering shader programs have so far made this feature out of reach for our one graphics rendering developer (me).
> 
>  I made a feature request for per-model silhouette edges and perhaps in the future we will find a simpler way to implement it that makes it feasible.
> 
> 	https://www.rbvi.ucsf.edu/trac/ChimeraX/ticket/4420
> 
>  Tom
> 
>> On Mar 25, 2021, at 10:09 PM, Andre LB Ambrosio <andre at ifsc.usp.br> wrote:
>> 
>> Dear all,
>> 
>> I wonder if it's possible to display silhouettes selectively in the same figure; for instance, displaying silhouettes only on structure representation (around sticks, spheres, cartoons and so on), but not around the maps or volumes that surround them.
>> Many thanks in advance, 
>> 
>> Andre
>> _
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