rapid prototyping

I am working on a casted arm and leg for a chair for a patio furniture manufacturer. I am sculpting the form in Rhino.

I have heard that you can save a closed polysurface in Rhino as a Solidworks file for prototyping. Is this true? Is there anything else I should know? Do I save the file as a certain file type, or do I have to export the file as something else.

I may be getting ahead of myself, but what is the cheapest way to make a prototype for a arm/front leg. Or, does it depend on the complexity?


—The grass is always greener on the other side.—

I dont use solid works but in proE i would imort the surfaces, merge them, and solidify and export as an stl. You may be able to do that in rhino. You can then get a RP wax model and investment cast it in aluminium. Did you want a solid metal leg?

dont recall hearing the term “polysurface”. aha. “patch models”! learn something everyday. cant you export as an iges and just use that?

Yes, I am working on a solid aluminum arm and front leg in one piece. How much is it for a RP wax model and what is the process (machine)? I am new to this, but I am assuming that stl has something to do with the prototype process.

I assume that you can massage the wax form if it needs it?

I can export as an iges, but I am unaware of what file that extension is.


machines vary. as does cost. best to research vendors. they could quote your part and answer questions.

i’ve considered going wax w something and massaging it. but the wax i’ve seen makes me wonder if too much massaging is wise. maybe someone can answer that.


sending from Rhino as an IGES, VRML, or ACIS works. Even if it comes into SW as Surface model, you can always patch it up and create solid geometry.

As a far as getting it made you can approach it any number of ways. Parts made from a number of 3D Printing machines can work. The wax process modeler is one, and you can cast directly to that (two step process). There is another machine that makes models where you can create the mold in the machine and then pour the metal directly to that mold. From Zcorp it is called Zcast. The molds made in the machine can take temp up to 2000* and they have to be non ferrous.

hope this helps

Seeing how generally these kinds of parts are quite large and would require a lot of building time. as well as material costs.
I would question if Substractive RP would be cheaper.
Get a Blue Foam (or wood if you’d go with a sand casting) of a approximate size of the overall part. Get it to the machine shop, get them to CNC mill 3 or 4 axis milling should do unless you’re doing a very complex geometry.
and get your local casting company to cast it for you.
I think it’s a direction definitely worth looking into.

Optionally you may ask your machine shop how much would it be to machine out of aluminum instead of foam. The machinnig time will rise as will the material cost but you may save on casting.

*Edit: At last you can print the layout orthos real scale and use those to shape foam yourself. and save money on machinning.

Hope this helps.

wax sucks for reductive modeling. TYpically you will have to just redo the model and send another model out. It IS relatively cheap, but very brittle. drop it and it breaks into a million pieces. The surfaces are clumpy and dont even cut well.

Investment casting is an interesting idea, but I have never been able to get satisfactory surface finish from the wax models

hello from Athens

I did the same thing a few weeks ago, i modelled a fruitbowl in Rhino and i expored the file in “stl” format. You have to be careful with the export parameters, if you want to take an accurate model in stl format. The most accurate model gives you, of course a larger file size. I used this stl model for 3d printing with a stratasys 3d printer. The result was perfect, in abs plastic, everythhing i modelled was there. The surface is a little bit rough so you have to use sandpaper after…
if you want to see the prototype check my web site.
it is the waffle fruitbowl , the last 2 photos
good luck

do you have more time than money? are you in school? if so, does your school have a sculpture department and aluminum casting capabilities? is the department friendly to ID students? you could shape the parts yourself out of wood, make a silicone mold, cast a duplicate in casting wax, coat in ceramic shell and cast.

or more money than time? here is another route:


as said before, you’ve got to penetrate the world of model shops and rapid prototyping

At my Ini we pay 36p per cm3 for fdm another place chrges a standard of £50m per run for sls.