How could I get image file data (eg. R component) to be converted into attributes in SOP level, if say it was on a grid?

The ‘attribfrommap’ SOP should do the trick.

Andy

Thanks Andy.

Hi,
See attached for a VOPSOP example

Rob

@circusmonkey: I am tying to accomplish something similar to what you have posted.

What I want for output is points on a grid only if the alpha from the image is not 0. How would I add points to a group or delete them from the grid while in VOPSOP context?

Basically knock out the alpha points only.

I modified your VOPSOP by changing the colormap to export RGBA. Then I compare the 4th value to greater than zero and route that to an attribute. One level up I have placed my new variable $MYAPLHACHAN into the Point SOP following the VOPSOP and I do get non-colored output where expected.

But how do I actually use $MYALPHACHAN to remove the points from the grid?

Use delete SOP > Operation to Delete by Expression > in Filter Expression:

$MYALPHACHAN < 0.1

Or in AttribWrangle:

if(@myalphachan < 0.1)
removepoint(0, @ptnum);

Thanks for the reply, the Delete after the VOPSOP does work but I am not sure why?

What exactly is the contents of the $MYALPHACHAN?
I assume it is some kind of array of data. Wouldn't I need a For/Each sop to iterate through the data with the Delete inside?