Using Polytrans from Okino to import Meshes to SW

Our office is converting part of our design process to SW. However,
we have an extensive collection of 3D drawings which use polyface
meshes to represent objects (Created in AutoCAD). I am looking for a
convenient way to get these into SW.


I have an older version of Okino's Polytrans software, and had some
success with it, though it did have some problems. I am wondering if
the new version is able to do better. I also know they have a special
module just for SW which I've not used.

Anyone here have any experience with this particular software and
converting meshes for SW?

Joe Dunfee

 

Polymeshes are approximations. The result of a polymesh to NURBS conversion
is an approximation of an approximation.

I would have a service bureau do some conversions first to see if it's even
worth it. If the models are prismatic, or mechanical in nature, It's
definately not worth the trouble.

Mark

 

I have beem using Polytrans for awhile now. Frankly, I have never had
any luck doing what you suggest. Depending on what the objects are,
you may be better off going the Geomagics route. I think you will be
nothing but frustrated trying to convert them any other way. I can
give you the name of a vendor that uses Geomagic if you'd like. They
may be able to help you.



Mike Tripoli

 

Can you tell me more detail about this approximation. I realize
polyface meshes cannot accurately represent curves. However, the items
I trying to translate are almost all representing square tubing. Is
the issue the number of decimal places the coordinates is saved at?

Aside from the square tubing, about 5% of the drawings I would like
to translate are things like theatrical lighting fixtures, trees, and
people. For these, the appoximations are acceptable.

Joe Dunfee

 

Joe,

It's mostly the fact that you'll end up with a bunch of dumb, poor
performing models at best. Poor performance of imported data is direcly
related it's relative accuracy. You'll find that even if the model is just a
simple box, the walls won't be flat or perpendicular. On top of this, it'll
just be a dumb blob. SW seems to treat all surfaces and faces as "potential"
solid elements. Because of this, it performs better with highly accurate
data. Poorly or inacurately defined geometry bring Parasolids "tolerant"
algorithims into play. This is a burden to the CPU.

I can model a piece of square tubing in about 15 seconds, so can you. With
configurations, this single model can represent any cross section, length,
or wall thickness, with a single mouse click. You'll probably spend much
more time trying to convert and import your old stuff than modeling from
scratch.

The best thing to do (in my opinion) is just leave your legacy data in the
original format. Use it as a reference to model SW data as needed.

Regards

Mark