[vtkusers] Raycasting, LOD, ...

[Lisa Sobierajski Avila]

Hi Frank,

I'll have to look into that. The logic is tricky for doing multi-resolution 
ray casting mixed with LOD props - at some point the prop must answer the 
question of whether it wants the image size reduced in order to achieve the 
desired rendering rate, but this is probably before the prop has even 
decided what LOD to use. This means there are competing decisions being 
made - the LOD prop will change LODs to try to achieve the frame rate while 
the ray caster will change image size, neither knowing about the other's 
decision.

In the future I'd like to add in a volume ray cast mapper that produces an 
image rather than going through the ray casting API - this way it can make 
its own decision on how many rays to cast. It will probably be a few months 
before I get to this though. Otherwise, it is best to either use the 
LODProp3D or AutomaticScaleAdjustmentOn but not both at the same time.

Lisa


At 02:48 AM 7/24/00, Frank Boettger wrote:
>Hi everybody,
>
>i'm using the raycaster for volume rendering. The volume is added via 
>vtkLODProp3D, and i have a bounding box
>added to the renderer as a vtkActor. AutomaticScaleAdjustment is on, i.e. 
>in interaction mode the number of rays are
>automatically reduced by the ray caster to achieve 'interactive frame rates'.
>This reduction of rays used for rendering is what i want for the volume, 
>but my bounding box now is rendered in less
>resolution as well and gets blocky. How can i prevent the bounding box to 
>become blocky, but instead always appear
>in the highest resolution?
>
>Thanks in advance,
>
>Frank
>
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