May someone could offer a good explanation about "check manifold"
May someone could offer a good explanation about "check manifold"
(OP)
May someone could offer a good explanation about "check manifold" which appears in many dialogs within CATIA V5
TIA
TIA





RE: May someone could offer a good explanation about "check manifold"
The tangent point is non-manifold, because there is zero thickness there. And that should be avoided. CATIA can handle it quite fine, but some other systems can't and it also can not exist in reality. There always should be, at least some, thickness there.
I just checked in the CATIA help and it says it is only available for curves... at least in the Join command. That's weird, can anybody explain?
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RE: May someone could offer a good explanation about "check manifold"
RE: May someone could offer a good explanation about "check manifold"
The issue is that you can't have more than 2 faces adjacent to a common edge.
John R. Baker, P.E.
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RE: May someone could offer a good explanation about "check manifold"
BTW, this forum really gathered a lot of professionals here, that's great!
RE: May someone could offer a good explanation about "check manifold"
In Azrael's example; is it manifold or non-manifold when the 3 curves are joined at a common point (such as a "Y") ?
What about John's example; is the partbody manifold or non-manifold when more than 3 faces share a common edge?
RE: May someone could offer a good explanation about "check manifold"
RE: May someone could offer a good explanation about "check manifold"
RE: May someone could offer a good explanation about "check manifold"
What you're describing is NOT an 'edge' but rather a 'vertex' or corner. Generally speaking, a vertex can be shared by an unlimited number of faces, or to put it another way, any number of edges can be joined at a common vertex.
As for your second question, what determines a manifold condition is NOT the edge/vertex nor the face/vertex relationships but rather the edge/face relationship. So to answer thae question, ANY situation were you are attempting to create a model where an EDGE is shared by MORE THAN 2 FACES. BTW, while it's fairly common for someone attempting to create topology where four faces share a common edge, having a situation which involves only THREE faces, now that takes some real creativity
There is also another, although generally more obscure, non-manifold condition and that is where an attempt is made to join two faces into a single model where NONE of the faces share a common edge. To visualize an example of this think of a 'T' where one face 'joins' the other at a mid-point on that face. This again would be considered non-manifold if you tired to treat it as a single topological body.
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
UG/NX Museum: http://www.plmworld.org/p/cm/ld/fid=209
To an Engineer, the glass is twice as big as it needs to be.