RE: please help rapid prototyping

From: Taylor, Tracy L (tracy.l.taylor@boeing.com)
Date: Tue Nov 18 2003 - 20:56:42 EET


Grant

You should be able to create the object your speaking of with Rhino for use in RP. Rhino has a good set of tools for creating smooth, watertight STL files. But make no mistake...Rhino is not for mesh modeling or editing. Rhino is not parametric and has a few other limitations but it is my tool of choice when someone sends me curves of any kind and expects a model in return.

For a car body the initial surface is usually fairly complex. But once you have defined your surface Rhino can easily offset most surfaces very well.

The general steps would be:

Create your surface.
Join all the pieces together.
Check for bad edges and make sure the only edges that highlight are on the periphery.
Offset the surface.
Loft the edges.
Join everything together. Now you have a solid.
Check for bad edges again. There should be none. If there are you can join them.
Export to an STL file.

Keep in mind that the greater the offset the more problems your likely to have lofting the surfaces together. Also the thicker the shell the more you will pay to have it built. For a 1/24 scale model (2"x4"x8" about) I usually use a thickness of .030" for SLS or SLA. Talk to your RP shop to make sure the model size and expected feature sizes are reasonable.

Good Luck

Tracy Taylor
Rapid Manufacturing Center
The Boeing Company
Canoga Park, CA

 

-----Original Message-----
From: Grant Harvey [mailto:harvey347@hotmail.com]
Sent: Tuesday, November 18, 2003 6:34 AM
To: rp-ml@rapid.lpt.fi
Subject: please help rapid prototyping

hello,

does the cad model to be used for rapid prototyping require to be a solid
model? can i use a surface model which fully encloses a volume???

i want to use the software rhino 3d to model a car body shell. if a solid
model is required how do i turn a surface model into a solid model and can
this be done on rhino 3d?

...i.e. could i loft a surface, offset this surface, join the two surfaces
formed together to give thickness and then use this for rapid prototyping???

also, if there is anyone who has used rhino, any chance you could describe
the methods taken to take your surface/solid model and make it into an stl
file?

many thanks for any help you can offer me,

Grant Harvey.

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