stream tracer from point with ray

Hi all !
I would know if there is a way to create a stream tracer from custom filter using a set of data (in my case 5 polydata vtk point representing polymer) and use a certain ray around it … there is such possibility ?

Do you mean the Stream Tracer With Custom Source filter?

I try to use the full box and the polymer as source ! I obtain 5 very close line (that looks one) what I need is to having an area around the polydata to use as source … or using the filter properly setting a ray around the source … I don’t know

Do you have any advice ?

I really don’t understand what you are asking. With the Stream Tracer With Custom Source, just set the volume with the vector field as the Input and some other data set as the Seed Source. The filter will trace streamlines from every point in the Seed Source.

I am guessing that you are asking how to place seed points. The only trick is to create a data set with points where you want to trace from for the Seed Source. You can use one of the sources provided by ParaView (such as Sphere, Plane, or Box) or a filter to modify an existing data set (such as Slice, an extract, or maybe Transform).

If the points in your Seed Source are too close, maybe you can try to first Transform them to scale the size up (scale greater than 1).

I’m maybe not well explain ! I’m able to use the filter properly ! but I want to increase the area around the polymer as source !
basically I guess your suggestion to create a sphere around the data is what I was looking for !
How can I create it around my polymer data ?

I can’t think of an automated way to do that. Your best bet is to look at the Information tab and create a sphere at the center of your polymer data and a radius as you wish. That said, if you are doing all that, you may want to just use the standard Stream Tracer and use its built in point source with the same center and radius.

Another approach might be, as I suggested earlier, to apply the Transform filter to your polymer data and scale it up to make it bigger.

But if I scale the polymer up, I still get just 5 line (one for each point) right ?

Yes, that is correct. Earlier you said that the 5 lines were so close that they looked like 1 line. I thought you wanted to see the 5 distinct lines. If you want more, then yes you will need to create new geometry with more points (with the sphere or point source).

ok !! thank you very much for your help ! I think now I have all the knowledge to proceed with my post processing !

have a nice week end

Dear Kenneth,

When you speak about transform filter may you explain me how to increase the size of the polymer (data) but respect to the same center ! basically I would like to increase but respect the same center of mass ! How can I do that ?