Edge Tracing and Effects

I am working on a small project regarding projecting mapping. What I would like to achieve are the effects in those videos:

I got as far as making the the geometrical objects and aligning them and also with help of some patches I found on this side I can use several projectors for one or more objects.

What I cannot figure out is how to get this tracing effect etc.

Some help would be great. Thanks in advanced.


try out vertex buffer to get the indexes over to B-spline, then use Line for example for tracing.


can you give us a patch pleaseee :-)

Hi I ll try to post something later on although it s an idea in a very early stage, anyway beware that there may be less painful ways to achieve it (writing a dedicated shader maybe?) and that 90% of the work is not the patch itself but the selection of the vertices over the time ie: a way to control it.

Here a starter idea, as mentioned before I guess there are far better ways to accomplish it, and I ll post some more stuff soon so we can try to work it out together, anyway have a look at it maybe you can come out with something better.

edgetracing-idea.v4p (11.6 kB)

A better version

Edge tracing idea II.v4p (13.2 kB)

And another “cheap” way to get the edge tracing effect.

edge_idea_III.rar (7.4 kB)

And one more, this is the most flexible one, although you ll have to create your own animation with timeliner or a MIDI sequencer, or parsing and XML file, whatever.

edgetracing-idea_IV.v4p (12.2 kB)

Hi Io

Your IV patch looks interesting. I like the way you’ve drawn the wire frame using a line.

The second line doesn’t seem to do anything though. What should be happening when I hit the toggle connected to the damper?


when you hit the toggle button three purple lines should start from one vertex and be drawn on three edges…

Works now. Thanks