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Cause for Mesh problems (brep) (by Thomas)
Hi guys,
so its been over a year now since I switched to Solve and I thought I could get around those red mesh defects with certain strategies like :
Make fillets by using the tangents (Bogentangente) and then drawing lines outside of the body to make the cut bigger than the actual part. This was a tip mentioned in the forum.
This also works for revolution operations or lathe. Making the sketch that is going to be rotated extend above the centerline so there are no problems with precision on the edge.
So in general all the mesh problems are a result of these "precision problems" close to edges? I orignally thought its mostly lines that go towards zero with another line like the tangents. Since I often use existing geometry to define new sketchlines this cause problems on many points.
Just thinking..
so its been over a year now since I switched to Solve and I thought I could get around those red mesh defects with certain strategies like :
Make fillets by using the tangents (Bogentangente) and then drawing lines outside of the body to make the cut bigger than the actual part. This was a tip mentioned in the forum.
This also works for revolution operations or lathe. Making the sketch that is going to be rotated extend above the centerline so there are no problems with precision on the edge.
So in general all the mesh problems are a result of these "precision problems" close to edges? I orignally thought its mostly lines that go towards zero with another line like the tangents. Since I often use existing geometry to define new sketchlines this cause problems on many points.
Just thinking..
(no subject) (by Paul)
Thomas,
There is a fairly good catalog of NURBS and mesh issues here:
https://github.com/solvespace/solvespace/issues/738
We've fixed a lot and there are several left. I'm not sure "precision" is the issue.
We definitely have problems when a curved surface meets tangent to a flat surface.
There are some other problems that look (to me) like a bug in the boolean intersection code. I say this because an intersection works great (thanks ruevs!) But the same geometry fails with union or difference.
There is one regression where the model works in version 2.3 but not 3+ This one we just haven't had time to track down which change broke it.
Coincident curves and surfaces can also cause problems, mostly in assemblies.
Just summarizing my understanding of these issues.
There is a fairly good catalog of NURBS and mesh issues here:
https://github.com/solvespace/solvespace/issues/738
We've fixed a lot and there are several left. I'm not sure "precision" is the issue.
We definitely have problems when a curved surface meets tangent to a flat surface.
There are some other problems that look (to me) like a bug in the boolean intersection code. I say this because an intersection works great (thanks ruevs!) But the same geometry fails with union or difference.
There is one regression where the model works in version 2.3 but not 3+ This one we just haven't had time to track down which change broke it.
Coincident curves and surfaces can also cause problems, mostly in assemblies.
Just summarizing my understanding of these issues.
(no subject) (by Thomas)
Thanks,
It seems I get at least one of these errors in every design and I´m running out of ideas to prevent them in some cases.
I´m currently doing mostly one part designs so it´s not a big issue after converting them to mesh, even if it has errors, it prints fine.
It happens mostly with difference and circles when they touch another feature.
I used intersection on some parts to make fillets, worked every time afair.
Does it help when I upload thos smaller models with errors?
It seems I get at least one of these errors in every design and I´m running out of ideas to prevent them in some cases.
I´m currently doing mostly one part designs so it´s not a big issue after converting them to mesh, even if it has errors, it prints fine.
It happens mostly with difference and circles when they touch another feature.
I used intersection on some parts to make fillets, worked every time afair.
Does it help when I upload thos smaller models with errors?
(no subject) (by ruevs)
Thomas, simple models that cause "red lines" (NURBS or mesh errors) are always welcome. You can attach them here or create a GitHub issue if you have an account. If your error seems similar to one of the existing issues in the link Paul gave you can just comment with your model attached.
(no subject) (by thomas)
Ok thanks, will do :)
(no subject) (by thomas)
I've attached them as zip collected in one issue. Deycribed roughly when it happened.
(no subject) (by ruevs)
Thanks!
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