First of all, you are very close. Mark("colors") to make it data, then pass
to Compute with the expression "a.x" to extract only the first component
(a.0 works as well).I wonder though if all this is necessary; you can set the isosurface value to anything you choose, so if you're doing this just to see a different isovalue then you're doing more work than you need..... Donna L. Gresh, Ph.D. Visual Analysis Group IBM T.J. Watson Research Center (914) 784-5049 http://www.research.ibm.com/people/g/donnagresh [EMAIL PROTECTED] Alan Scheinine <[EMAIL PROTECTED]>@opendx.watson.ibm.com on 02/13/2002 12:09:28 PM Please respond to [email protected] Sent by: [EMAIL PROTECTED] To: [email protected] cc: Subject: [opendx-users] transfer function I want to change the data values of a three-dimensional field using a transfer function. The colormap widget seems ideal for specifying the transfer function interactively. How can I turn a component of that color field into a single datum for each point of the field? I take the original data and use Colormap and then I combine the original data with the colors using the module "Color". The result is a color field. But now I want just one component of that field, for example red, to be the data. I took the original field and am using the module Replace to the data part of the field but the isosurface module fails and I suppose that the field I am creating does not have the right type of "data" component. I should add, I take the output of color and use Mark to change it to data. But how do I pick one component? I tried inserting various modules such as Compute and Extract but I have not found the right combination to make the color field into a single-component data field. I do not know if my explanation is clear, I fear it is not, but anyway the idea is simple. I have a field with simple rectangulare connections and one data component of type unsigned short. To simplify, suppose the values are float from 0.0 to 1.0 . I want to convert 0.5 to 1.0 and convert 1.0 to 0.0, that is a transfer function the makes the middle values have the largest values, in that way the isosurface will show the part that is interesting, around 0.5 . The only tool that I see already available for interacting with a transfer function is the colormap Editor, so I am trying to find a way to use that. Thanks for any help you can provide, Alan Scheinine Email: [EMAIL PROTECTED]
