Invalid Brep & Surface in Grasshopper



Hi David,

It would be super amazing if the “Invalid Brep/Surface” could be fixed in the next Grasshopper version.

Many thanks in advance :slight_smile:

(David Rutten) #2

We can’t fix it unless you tell us how you made an invalid brep. What component generated it? What were the inputs?


It was made by trimming surfaces (formed from big spheres) with smaller spheres (added by generating points over the surfaces).
The result was a surface (formed from a part of a sphere), with circular holes in it (resulted from the smaller spheres).

There were many surfaces, and most of them were okay, yet when the number of the small spheres would increase, some of the resultants would become invalid.

This was then solved by using brep/brep intersect (to get the circular curves), then trimming the big spheres with the resultant circular intersections, which gave better results without “invalid surfaces”. This latter solution was okay, yet it took much more time to execute, and the definition extremely slow and not responsive.

Although I have found rather a slow solution to that, this may occur in other instances, giving “invalid breps/surfaces”.

(David Rutten) #4

Can you upload the gh file so I can repeat the problem?


Ok, I don|t have the file currently. Will upload it in few days.


Invalid_Srf.3dm (749.7 KB) (84.1 KB)
Hi David,

So, I have attached here the files. Since it is office work, I have internalized the invalid surface and baked the edges in a layer so that you find it (as it is far from the origin).

Basically, this is the result of solid difference of many spheres (the main big surface), then trimming with smaller spheres.

I have solved this by using the intersection curves and then trimming the surface with the curves-instead of with spheres, and it worked out fine. However, this solution proved to be extremely slow, taking hours to respond every time I make a single change.

I hoped not to have “invalid” surfaces/breps in the first place.

In any case, kindly take a look.