Rhino or Sketchup?

[DaKra]

I'm gonna start figurin' out 3d printing.   Narrowed my software choices to Rhino & Sketchup.  Anyone with any experience care to comment?  Looking for nudges towards one or the other.   

Dave
 


 

[nalmeida]

The simplest answer:

Sketchup: Easier to use but less features (The absence of real circles really bugs me)

Rhino: Harder to use but a lot more features

I like and use them both!

[finescalerr]

Regarding circles, Marc (who uses Sketchup a lot) imports 2-D drawings and "extrudes" them. So it would seem simple to create a circle in AutoCad and import it, thus obviating the problem. N'est-ce pas? -- Russ (who also wants to learn SketchUp when he finds time)

[nalmeida]

As far as I'm aware even if you create a circle using a cad program (I use Corel Draw by the way) when importing Sketchup ALWAYS converts it to a polygon, the only thing you can do is to raise the number of sides. From what I read this has been a compromise from the beginning as the Sketchup team always perceived it more as a sketch program rather then a a full featured 3d option.

[finescalerr]

Oh. -- Russ

[78ths]

I will stick with Viacad - has full 3D features, no issues printing parts and it is only 100.00 (much less when on sale) and one of the very few apps that will let you swap files between Apple and PC. Also one of the few apps that uses a Apple interface which may pose a learning curve to PC users. Turbocad is built on the Viacad engine.
cheers Ferd

[JESTER]

(The absence of real circles really bugs me)

Huh? What do you mean real circles? I made a circle yesterday.

-

[Frederic Testard]

Well, I'm not sure it's such an issue (I mean the circle). There's no visible difference between a circle and a 180-edge polygon.

[nalmeida]

"All geometry in SketchUp is comprised of straight lines, including circles and arcs.  By default, SketchUp creates circles with 24 sides and arcs with 12 sides."

Additional information:

http://www.google.com/support/forum/p/sketchup/thread?tid=050054326827fa41&hl=en

[clevermod01]

All 3d software except for true CAD systems and one spline modeler I'm aware of (and that one won't work with RP) tessellate to polygons at some point. Sketch up seems limited but it's actually pretty powerful. It just uses an unusual construction paradigm. You might look at Blender its open source and free yet very powerful. I work with animation software so I don't have any technical experience with true cad programs. My brother is an autocad guy . I'll ask him if circles tessellate to poly or not
In general If it's not splines its flat polys, weather they look curved or not.

[DaKra]

Another question-- can either of these programs, or perhaps some other one, reduce a 3d drawing to 2d drawings for each surface?  Like convert a hollow pyramid into a set of 5 panels? 

In other words, is there a feature to create a set of flat kit parts from a 3d rendering?   

Dave

   

[Frederic Testard]

I've recently started to discover CoCreate Modelling Personnal Edition (free download), and they have a feature that looks like what you say. Whenever you object has a face you can choose this face as a working plane (don't remember the exact name) and while I haven't tried it, I'm almost sure you can export the drawing of this working plane in 2D. And I guess all serious 3D cad softwares have such a capacity.

[marc_reusser]

Another question-- can either of these programs, or perhaps some other one, reduce a 3d drawing to 2d drawings for each surface?  Like convert a hollow pyramid into a set of 5 panels? 

In other words, is there a feature to create a set of flat kit parts from a 3d rendering?   

Dave

   

I don't know of any 3D or CAD program (at least not one under 3-5K) that will do that, the requirements are just too great....due to the fact that everything in 3D is drawn w/ a Z-axis....and it also would need to know how to extrapolate what piece of a 3D drawing would form an individual component...and how in say a pyramid, does the extrapolation deal with shared lines being edges of different components/parts.  ACAD does have a function/lsp called "Flatten"...this will bring all the Z-axis points to "0"....but this directly drops them to "0" in respect to their 2-D location...IE. when looking down at a 3D pyramid in 2D, the triangles it creates are smaller/foreshortened...than they are in the actual 3D form.....or as they would be if they were "rotated" into flat/"0", as would be needed for true part/side extrapoltion if you wanted to say laser cut them.

Marc

[Frederic Testard]

Well, Marc's comment makes me wonder if I haven't been too optimistic. I'll have to check it.

[marc_reusser]

It could be done manually...would take a lot of work...or an LSP routine, that say on a pyramid would go something like:

copy>paste-in-place>rotate(input: basepiont/rotation degrees). ... this command/sequence would need to be done, for all four sides. The reason for the copy>paste-in-place, is due to the shared lines forming the sloped edges of the pyramid...you would need to leave those there/in place to create/rotate the next side.

This process could be shortend, if you gave the proces and ther required pieces some thought before building the 3D pyramid....basically create one side....then mack this side into a group or component, copy/duplicate the component 3 more time and rotate/place the components to form the pyramid....then late when you were extrapolating the cutting diagram/template, to get them to "0" you would just need to rotate each side.

Marc