[Chimera-users] graphics performance: amira v. chimera

[Dougherty, Matthew T.]

What's wrong with just using chimera?  If it's just that it's too 
slow, then please file a bug report and provide a sample data file.

>> First of all I think Chimera is a great package and I highly recommend it, regularly.
>> It is one of the very few softwares that actually adheres to specifications correctly (eg VRML).
>> Not complaining about the speed, it is more than adequate for animation.
>> Appreciate the tradeoff on speed & quality, not clear on how you are doing it in opengl.
>> no bugs to report.

>> after years of seeing most viz packages fail the same way on the opengl, 
>> I am impressed that that you got it the best I have seen, short of ray tracing.
>> just surprised the commercial packages (at least 5 come to mind) that can't keep up.

>> as for using chimera exclusively, I have to integrate software 
>> (3dviz, photoshop, FCP NLE) depending on what users give me to start with.
>> be nice just to use only one...
>> I just try to figure out who is the best at what they are doing, and get data in and out of it.

>> thanks, Matt


Typical transparency implementations require that the graphics primitives 
be drawn in a back-to-front order.  It sounds like amira is just drawning 
the primitives in the order in which they are given in the vrml file, so 
the transparency effect is haphazard.  You would probably get better 
results from a dedicated vrml viewer, like Octaga, BS Contact, Flux, 
FreeWrl, etc.  Chimera uses an alternate, 2-pass, transparency technique 
that works well, but is not perfect (except within surfaces, where chimera 
does depth-sort the triangles).

 	Greg Couch
 	UCSF Computer Graphics Lab

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