What CAD systems interface to TrueGrid®?
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Answer:
TrueGrid® uses the IGES interface so the answer is all CAD systems
with an IGES output.
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The IGES interface is used because the projection method in TrueGrid®
only requires surfaces.
Many mesh generators have a direct link to specific CAD systems.
A direct link to a CAD system's data base accesses solids which would
be of little use to TrueGrid® since TrueGrid® is not based on
solids.
This is also why we recommend that the CAD operator building the CAD
geometry should not take extra
steps in decomposing the geometry into simple solids. This only complicates
the geometry.
In contrast, a solids model (or B-Reps) is typically used by mesh generators
because most mesh generators are using automatic mesh generation algorithms.
These automatic mesh generation algorithms are in use because the majority
of the market prefers ease of use mesh generation over quality meshes.
Basically, TrueGrid® uses
the IGES interface to CAD systems because it offers the highest quality meshes.
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Sometimes this question is asked because someone in the past used IGES
geometry to build a hexahedron mesh and it was difficult because the
tool used to generate the mesh required that the surfaces meet
almost perfectly. A lot of time was required to fix the geometry
so that it could be meshed.
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Again in contrast, TrueGrid® is unusually tolerant with
imperfect IGES geometry. This is because of the projection method.
In TrueGrid®,one composes many surfaces in a very easy fashion without
changing the geometry.
When several surfaces are composed, it does not
matter if they have gaps or overlaps. When an edge of the mesh is
projected to the intersection of two surfaces or composite surfaces,
it is automatically done using
the tangent planes. So if there is a small gap between the surfaces,
the edge will be projected to the intersection of the tangential
extension of the surfaces. TrueGrid® always finds the intersection.
This is why IGES geometry is ideal for TrueGrid's®algorithms.
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www.truegrid.com/FAQ/cad.html April. 4, 2008
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