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Sarford
01-22-2009, 04:51 AM
Hi,

A client of mine asked for a model of one of my designs to be used for a rapid prototyping test. I seem to recal that the model has to be 'water thight' to be usefull.

Does anyone have experience with rapid prototyping, and how can I check if a model is water thight? Can I also use a model made out of different parts or does the model has to be one continues mesh?

AbnRanger
01-22-2009, 05:06 AM
Hi,

A client of mine asked for a model of one of my designs to be used for a rapid prototyping test. I seem to recal that the model has to be 'water thight' to be usefull.

Does anyone have experience with rapid prototyping, and how can I check if a model is water thight? Can I also use a model made out of different parts or does the model has to be one continues mesh?Maybe I'm misunderstanding what they mean by "water tight", but it seems to me that it is a figure of speech, meaning that it can have no flaws whatsoever...and the reason is that STL format is not editable on the production side. It's about as useless for them as it would be if someone gave you a model, but instead of all quads, it was all tri's.

They are using nurbs-based BREP formats that is entirely dissimilar to Polygonal modeling.
I found PowerNurbs Pro for 3ds Max as the only method to model in one of these types of programs and have it translate cleanly to a solid surface BREPS format

akademus
01-22-2009, 05:23 AM
Water tight means just that. It shouldn't have any holes or unmerged points and such. If you have a character imagine it's empty inside, and if you pour water in it it should't leak anywhere!

No overlapping vertices as well. If you're using subpatches, make sure there is no point over point (you know, when model looks ok in subpatch mode, and like crap if you're back to ordinary polygons).

Ratboy
01-22-2009, 07:35 AM
I've been doing a lot of watertight work over the last few years. I've found this utility:

http://marcam.fischer-dev.de/downloads.14.en.html

VisCAM View to be essential for tracking down mesh errors. It'll find open edges, coplanar triangles, and intersecting triangles. You'll still have to fix those yourself in Modeler, but at least you'll know where to look.

If you need a watertight mesh turned around in a hurry, PM me and we can work something out :)

Sarford
01-22-2009, 04:42 PM
@ AbnRanger: Thanks, I'll look into that STL format. Maybe my clients contact has a way to change LWO or OBJ to STL. Nurbs modeling is a big no-no for me. I've done some tutorials on that way back in 3DS MAX version 4 I believe, never realy got it.

@ akademus: Thank you, I'll make sure the model is clean! There is no subD modeling involved so I hope it isn't much of a problem, but seeing that I made this before I could model properly, it might just be.

@ Ratboy: Wow, thats a good find man! I'll try it out. Thanks for your offer, but since this is a test, it is all for free.

Thanks for the help guys!

Jirapong
01-22-2009, 04:58 PM
STl with nurbs is usually what the manufacture looking for.
I, in the past , used Formz to import LWO and export again in STL format.
However, if you use Rhino you can do the same and also if you have T-spline plug-in you can convert polygon models into nurbs.

Good luck,

JamesCurtis
01-22-2009, 05:20 PM
Here are tools for impoting STL format into LW Modeler and one for Exporting LWO from Modeler to STL. Works great in LW9.6.


http://www.chromecow.com/downloads/lscript/shm-stl-tools/

Ratboy
01-22-2009, 05:20 PM
STL's a pure triangle format, isn't it? I didn't think it could do nurbs.

I got the Chrome Cow STL import & export plugins from here:

www.chromecow.com/2006/03/15/new-version-of-shm-stl-tools-v111/

The site doesn't seem to be responding, though.

AbnRanger
01-22-2009, 05:57 PM
What they get is a model that is faceted. It is not something they can tweak or edit, but if the model meets all the specs and was clean, they should be able to use it to manufacture from.

That's why it needs to be perfect before exporting via STL.

But if it's modeled in Nurbs, like in Rhino or Max (PowerNurbs Pro exports to BREPS formats like IGES...which the production crew can rework or make slight adjustments to if needed), it can be exported in a format that IS editable on their end. Solid Surface programs essentially use NURBS.

lesterfoster
01-23-2009, 07:29 AM
I have some experience with rapid prototyping. My avatar is a photo of a 3d print that I made with Lightwave. What type of 3d printing are you looking for. There are some differences with how each method of 3d printing works.

One of the best people that I know of is 3D are to part (http://www.3darttopart.com/index.php). I have gotten a lot of parts printed in 3d from 3d art to part. They can take your raw lw files.

If you are using subpatch for your object, freeze it. After that. You are going to half to check it for holes. I use LW CAD to help do that. Use the CAP HOLE tool.

This link is from 3d art to partís website. It has some info on how to make your objects for 3d printing.
http://www.3darttopart.com/modeling%20info.php

I am running out of time right now. I hope this helps. Maybe I can help some more after I get back from work.

If you do not have LW CAD, there are other methods to fined and repair any errors on your model.

PS. Be sure to make any and all changes to a copy of your original file. Not your original file.

Mr Cookie
01-23-2009, 11:10 AM
I do prototyping all day long I use LW9.6 for modeling then import the LWO in to Blender 3D then export as STL format Blender dose a good job, use the new ver of .Blender.
Thanks

cscardinal
04-14-2009, 11:36 AM
But will it be able to build dimension specific models, not just "freehand" stuff?

i.e. a 2"x2" square with beveled edges and a 1" raised circular center portion. It has to be correct for it to be usable to me. I *really* don't want to have to learn yet another program!

Thanks

CSC

BeeVee
04-14-2009, 02:04 PM
LightWave has a great feature in that if your object measures 1" in Modeler then you can be sure it will print directly out at an inch.

B

Valter
04-16-2009, 07:09 PM
Has someone using Wings 3d for import LWO and export STL?? does works fine??

Thanks