[vtkusers] COLOR_SCALARS in the ASCII Legacy Format

[Gerrit Groot]

Hi,

I'm new to this mailing list and hope I'm not asking for something obvious. Searching on the web, I couldn't find the answer, so I subscribed. (In fact I don't even know what a mailing list exactly is, but anyway...)

My question is about the Vtk Legacy File format.

If I want to give a color to, for example, points, I can use COLOR_SCALARS, but the variable definition in COLOR_SCALARS remains unclear to me, especially beyond a certain extend. I use paraview to view my results.

About the format now. So far, by trial and error I discovered the following:

In the header I give "COLOR_SCALARS name number"

For number=1:
- The color varies from black (0.0) to white (1.0)

For number=2:
- The first value gives the greyscale (0.0=black and 1.0=white) and the second value the transparency (0.0=transparent; 1.0=fully opaque)

for number=3
- The three floats seem to represent rgb values from 0%=0.0 to 100%=1.0

for number=4 it becomes unclear
- Here I expected the fourth value to be the alpha transparency, but at least visualising with ParaView, the fourth value does not seem to have any effect at all!

Moreover, paraview seems also to accept number=5, number=6 etc.

My questions are:

* What is the fourth value? And why doesn't it have any effect?
* How are the COLOR_SCALARS defined for number>4?

Thanks in advance,

Gerrit