[vtkusers] Transparency Problem in Many Actors

[John Biddiscombe]

It's a tricky problem. When multiple transparent actors are overlapping in world space, they need to be rendered back to front. If the actors are all distinct, then setting the culler to draw back to front with depth sort polydata on each one will help. If the actors all overlap in a complex way, you'll have to either accept a less than perfect result, or combine all the polydata into a single polydata object (vtkAppendPolyData), depth sort that and then render. (but now you'd only have one actor which might be detrimental to yuor picking etc).

For a perfect solution we'd need a new mapper (say vtkMultiPolyDataDepthSortMapper) which would depthsort multiple polydata objects and then render them correctly. It'd be tough to get right unless all polydata objects were using the same attributes and render options - and would be quite a bit of work.

JB


> -----Original Message-----
> From: phoenixzz at sina.com [mailto:phoenixzz at sina.com]
> Sent: 18 August 2003 09:36
> To: vtkusers at vtk.org
> Subject: [vtkusers] Transparency Problem in Many Actors
> 
> 
> Hi,all user！
> 
> 	   I used some actors in my Render and I want to set 
> different colors and transparencies to these actors. But I  
> got the error thing. Some Actors in front are disappeared.
> 		
> 		So I used the vtkDepthSortPolyData, but this 
> class is only used in one Actor. Then I can not set different 
> colors and transparency on my actors.
> 
> 		Please help me, and give me some advice. Thanks!
>  
> 
> 
> Phoenixzz
> 
> 
> 
> 
> 　　　　　　　　phoenixzz at sina.com
> 　　　　　　　　　　2003-08-18
> 
> 
> 
> 
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