[vtkusers] RayCasting through two datasets

[Lisa Avila]

This will "sort of" work, but keep in mind that you will see some artifacts 
on the data shifted up due to the fact that a thin shell of the lower 
values will exist on the upper values at the zero / non-zero boundary. This 
won't be too horrible if you first threshold the upper dataset based on the 
first non-transparent value in your transfer function, and your transfer 
function ramps up fairly quickly. Alternatively, if you switch to nearest 
neighbor, or use the classify first option this artifact should go away 
(but the image may appear more "voxelized").

Lisa




At 03:48 AM 3/5/2004, Benjamin King wrote:
>Hi Martin,
>
>let's say the maximum of the first dataset is less than m. Then you could 
>add m to all non-zero values of the second dataset and finally add the two 
>datasets. Then the part of the transfer function below m is for the first 
>dataset and the part above m for the second.
>
>Best regards,
>   Benjamin
>
>>I have a problem with Raytracing. I have two datasets (vtkImageData) with 
>>the same size and at the position where the scalar value of one datasets 
>>is not zero the scalar value of the other datasets is zero. So, my 
>>problem is I want to merge the two datasets and raytrace through them, 
>>but both datasets should have different transfer functions.
>>how can I make this?
>>
>>friendly greetings,
>>Martin.
>
>--
>Benjamin King
>Institut für Medizinische Informatik
>Medizinische Hochschule Hannover
>Tel.: +49  511  532-2663
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