Detect overlapping surfaces



2 list

A: surfaces
B: surfaces

I would like to ‘detect’ overlapping surfaces A with surfaces B
(in other words; surfaces which touch each other ánd lay in the same plane)

There is the ‘collision one|many’ component, which does detect if 2 surfaces touch each other. (correct).

However the component, gives also an collision if a surface only collides with an surface boundary.
So also if this boundary is part of a surface which lays in another plane.

2021-12-17 - Test overlapping (colliding surfaces).gh (12.8 KB)

Surface A is only overlapping with surface 2:

Any suggestions how to overcome?

Thanks! :slight_smile:

Hi -

Check if the normals point the same (or opposite) way.

How about using a slightly smaller one in order to avoid sharing edges?

Hi @HS_Kim,

smart Idea!
Unfortunately this solves the problem only partly.

If the 2 surfaces collide on exactly the outer edge (as in this example), it works correctly.
However, it is also possible that the colliding surface, is present perpendicular in the ‘middle’ of Surface A.

In this case it would not work :frowning:

But we are getting close :slight_smile:

any other suggestions?


Thanks again! :+1:

The same goes with the obstacles…


Ahh thanks again!
Yep, getting closer and closer.

Unfortunately it is also possible that the surfaces go ‘trough’ each other (while laying in another plane).

So it more of an generic problem.
Sorry I didn’t explain it this detailed earlier.

Any suggestion?

btw, how do you make such a nice ‘printscreen’ of the model on your canvan (right-bottom of your picture)?

Thanks again! :slight_smile:

I guess you are not checking the normals then…

1 Like


Ahh yep that could be an solutions!
The only thing is, I don’t know how I can make this.
As it is possible that List A and List B consist of multiple surface.

Would it be possible to make an example on how you would do this?

Thanks again! :slight_smile:

2021-12-17 - Test overlapping (colliding surfaces) (13.5 KB)

Something like this, perhaps?

2021-12-17 - Test overlapping (colliding surfaces) (13.8 KB)