work with faces which normals point inside a solid

[Anonymous]

Hello,

I've assumed, that normals of all faces of a solid point outside the solid.
But in the first example of my project I can find a face, which normal point
inside. Please see enclosure.

My question (1): Under which circumstances occur such faces. (2) Can I
detect such faces with another feature besides the normal?


And my next question(3): Whats the diff. between Edges and EdgeUses. I guess
that I can assume, that the outer/enclosing EdgeUses of a face always? are
directed counter-clockwise to the face normal, if the normal point to me!?

Especially the inside directed normal seems to be a problem for my
traversing tasks.

Environment: IV2009/2010 and vba/vb.Net
Thank you in advance.


doc snyder

[Anonymous]

Someone else ran into a similar issue recently. The thing you need to be
careful of is where you get the normal. You need to use the
SurfaceEvaluator object that you get from the Face.Evaluator property. The
normal returned by it will always point out of the solid.

Edges define how faces connect to one another and are associated with 3D
curves. EdgeUse objects define the boundaries of a face and are associated
with 2D curves. The 2D curves are with respect to the 2D parametric space
of the face the EdgeUse is associated with. For almost all traversal you
only need to use the Edge object.
--
Brian Ekins
Inventor API Product Designer
http://blogs.autodesk.com/modthemachine

[Anonymous]

Brian, thank you for your quick answer. Your hint really helps me.

doc_snyder





"Brian Ekins (Autodesk)" schrieb im Newsbeitrag
news:6323861@discussion.autodesk.com...
Someone else ran into a similar issue recently. The thing you need to be
careful of is where you get the normal. You need to use the
SurfaceEvaluator object that you get from the Face.Evaluator property. The
normal returned by it will always point out of the solid.

Edges define how faces connect to one another and are associated with 3D
curves. EdgeUse objects define the boundaries of a face and are associated
with 2D curves. The 2D curves are with respect to the 2D parametric space
of the face the EdgeUse is associated with. For almost all traversal you
only need to use the Edge object.
--
Brian Ekins
Inventor API Product Designer
http://blogs.autodesk.com/modthemachine

[Anonymous]

Doc,

I suspect the discussion Brian mentioned is this one
https://mail.google.com/mail/?ui=2&view=bsp&ver=1qygpcgurkovy

--
KWiKMcad
Kent Keller
"doc snyder" wrote in message
news:6323925@discussion.autodesk.com...
Brian, thank you for your quick answer. Your hint really helps me.

doc_snyder





"Brian Ekins (Autodesk)" schrieb im Newsbeitrag
news:6323861@discussion.autodesk.com...
Someone else ran into a similar issue recently. The thing you need to be
careful of is where you get the normal. You need to use the
SurfaceEvaluator object that you get from the Face.Evaluator property. The
normal returned by it will always point out of the solid.

Edges define how faces connect to one another and are associated with 3D
curves. EdgeUse objects define the boundaries of a face and are associated
with 2D curves. The 2D curves are with respect to the 2D parametric space
of the face the EdgeUse is associated with. For almost all traversal you
only need to use the Edge object.
--
Brian Ekins
Inventor API Product Designer
http://blogs.autodesk.com/modthemachine

[Anonymous]

Sorry, I am not sure where that link came from. Try this one

http://discussion.autodesk.com/forums/thread.jspa?threadID=758602&tstart=0

[Anonymous]

@KentKeller

Thank you for the additional information. I hope,
there are not so much 'false friends' like this in the Inventor BRep API for
beginners.

(...Getting oFace.Geometry.Normal is getting the
normal from the underlying
geometry, which doesn't know anything about the
face it is associated with. ...you need to use the
SurfaceEvaluator )

doc_snyder

style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">

<KentKeller> schrieb im Newsbeitrag
href="news:6325406@discussion.autodesk.com">news:6325406@discussion.autodesk.com...

Sorry,
I am not sure where that link came from. Try this
one

http://discussion.autodesk.com/forums/thread.jspa?threadID=758602&tstart=0