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View Full Version : Just learned LW models not good for Industrial Design (the hard way)



BH Blackfly 105
02-25-2011, 01:13 PM
Well,

I sent an obj file to a RPT company and found out the obj file was not going to work. I was trying to save the company some money by using LW

I downloaded an exporter for STL format and exported my model as an STL.

After reading a number of posts, LW was the wrong solution for this project. :censored:

So now we have LW 10, all I really have been able to take advantage of is the VPR.

I admit I am not a "well seasoned" modeler but I have been in the 3D scene since '97 when it was at it's infancy.

I have been considering what direction to take with advancing my skills in 3D modeling, and after this experience, I'm going to look elsewhere.

OnlineRender
02-25-2011, 02:09 PM
Lifes a ....... ,gutter . why didn't obj format work ?, was there not a work around , port to another app ? I agree maybe another method may benefit your workflow . but LW and ZB can be just as powerful , but it depends what field you work in ...

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edit I don't know enough about STL format

BH Blackfly 105
02-25-2011, 02:22 PM
basically, the RPT company uses Lightwave and said my model was just a wire frame and not a sold model.

If I had used NERBS I would have been successful.

OnlineRender
02-25-2011, 02:25 PM
sucks

kopperdrake
02-25-2011, 02:25 PM
If you're going to produce anything for production, you need a solid modeller. You *should* be able to get results from certain RPT methods, but they'll be from polygon-based models and not true to anything a CAM system would output, although very close visually. Polygon-based systems, such as LightWave, are suitable for lovely visuals, but not suitable (as you've found out) for production ready models.

Whilst I don't personally use it, look into Rhino. We have a couple of design clients that use it for concept work before handing us the files to work up.

kopperdrake
02-25-2011, 02:30 PM
basically, the RPT company uses Lightwave and said my model was just a wire frame and not a sold model.

If I had used NERBS I would have been successful.

What RPT were you looking at? I've given .lwo files to a company in the states who did SLS models and they did the conversion their end. Same for a company over here, and also check out shapeways.com - they accept STL files, and also have a good run-through of how to make sure your model will work.

Reading your quote above, were they trying to say your object wasn't 'water-tight', ie it had holes in the geometry that would make their system believe it was a very complex wafer thin object rather than a solid chunk of something? Seems strange that an outfit who use LightWave themselves wouldn't be able to help you further in your situation :/

Surrealist.
02-25-2011, 02:36 PM
There has to be a way to convert a model.

If you download Blender 2.49 there is a STL exporter. Never used that exporter But Blender is free and you can import .lwo as well as many other object formats. Maybe it will work better. Not sure, but you could try.

JeffrySG
02-25-2011, 02:52 PM
It's also possible that the issue was that the models were not built the correct way for RPT. There are many things you need to 'look out for' when building a model for RPT that you don't otherwise need to worry about.

Check out this list of items to be aware of:
http://www.shapeways.com/tutorials/things-to-keep-in-mind

I know many people here have used LW for RPT output but it might vary based on what type of 3d printer you would be using, etc.

Snosrap
02-25-2011, 02:54 PM
Lightwave, Maya, 3D Studio Max, modo, etc. are surface (polygonal) modelers. Manufacturing can't do much with the models produced from these apps. However it is possible to export .stl's for prototype 3D printing, just make sure it's "watertight". We do this all the time. There is an STL import/export plug-in for LW (SHM Tools by Chrome Cow) - it's free.

Surrealist.
02-25-2011, 03:48 PM
Both of those suggestions sound correct to me. Seems if there was something wrong it was either in the conversion or modeling stage.

I think it would be a good idea I think to provide more information of your situation in the support forum and get some more specific advice to solve your issue.

Lewis
02-25-2011, 04:28 PM
Yep, I've exported with that SHM STL exporter several model/pieces and they've all been successfully made as real world objects so it's not LW it's the user error ;).

But if you are going to do that very often then learn some of SOLID modelers who can do NURBS.

cresshead
02-25-2011, 04:41 PM
maybe have a look at formZ, that's a solid modeler or delcam powershape if you need to do alot of this type of work.

formz
http://www.formz.com/

delcam
http://www.delcam.co.uk/

Silkrooster
02-25-2011, 05:41 PM
Just a suggestion, but take a look at Turbo Cad. It has a solids engine, so it can model both solids and surface. Plus it can use Nurbs. Look at the features list, as I think you need to purchase the "pro" version to have access to the solids engine.
Turbo cad is provided by IMSI. It costs, but is cheaper than autocad. It has decent import/export formats as well including autocad, obj, dxf, and others.

Titus
02-25-2011, 06:34 PM
Well,

I sent an obj file to a RPT company and found out the obj file was not going to work. I was trying to save the company some money by using LW

I downloaded an exporter for STL format and exported my model as an STL.

After reading a number of posts, LW was the wrong solution for this project. :censored:

So now we have LW 10, all I really have been able to take advantage of is the VPR.

I admit I am not a "well seasoned" modeler but I have been in the 3D scene since '97 when it was at it's infancy.

I have been considering what direction to take with advancing my skills in 3D modeling, and after this experience, I'm going to look elsewhere.

I've printed some models exported from LW as OBJ. It was cumbersome but doable (their software has to make some computations to prepare the model), I'm sure this is the problem with that company, they don't want to spend time making the model work for the printer. Alas! I know people who printed models from RenderMan normal displaced files:

http://www.productdesignforums.com/topic/873-displacement-for-cad-models-and-rapid-prototyping/

Matt
02-25-2011, 06:41 PM
Lightwave, Maya, 3D Studio Max, modo, etc. are surface (polygonal) modelers

This is slightly incorrect, they are just polygonal modelers, "surface" is usually referred to for nurbs based modelers such as Alias etc.

- - - - -

And to add to what others are saying ...

All rapid prototyping firms that I've ever come across convert / mesh to STL files, so LightWave (if frozen at a pretty high level if you want smooth parts) can certainly be used for this.

As others have mentioned, watertight (no holes, all points merged etc.) models are needed.

What I wouldn't use LightWave Modeler for (or _any_ polygonal modeler for that matter) are parts that are to be manufactured for actual real production products. They are simply not designed for this.

SolidWorks and the like should be used, it's what they are intended for.

Snosrap
02-25-2011, 07:06 PM
Oh okay. Can the likes of Alias and Rhino models be brought into SolidWorks or Inventor if they are surface modelers? Why hasn't any developer found a way to bring polygonal models into solids based apps? I talked to Robert Lansdale from Polytrans a couple years ago and he told me it was technically impossible. :screwy:

Titus
02-25-2011, 07:33 PM
Oh okay. Can the likes of Alias and Rhino models be brought into SolidWorks or Inventor if they are surface modelers? Why hasn't any developer found a way to bring polygonal models into solids based apps? I talked to Robert Lansdale from Polytrans a couple years ago and he told me it was technically impossible. :screwy:

A surface is a mathematical description of an object, imagine something like sphere(0,0,0,1,1,1), cylinder (0,0,0,1,1), etc. Maya has the feature to transform SDS to NURBS and back, so it's doable.

Silkrooster
02-25-2011, 09:34 PM
Oh okay. Can the likes of Alias and Rhino models be brought into SolidWorks or Inventor if they are surface modelers? Why hasn't any developer found a way to bring polygonal models into solids based apps? I talked to Robert Lansdale from Polytrans a couple years ago and he told me it was technically impossible. :screwy:

I wouldn't say it is impossible. Some of the cad programs can convert between the two type of models. I would say the important portion is the accuracy of the object.
For example you wouldn't model a hard drive platter in lightwave and expect the proper clearance when creating the prototype on a CNC machine. Sure it could create it, but what are the odds of the platter crashing?

kopperdrake
02-26-2011, 05:43 PM
Oh okay. Can the likes of Alias and Rhino models be brought into SolidWorks or Inventor if they are surface modelers? Why hasn't any developer found a way to bring polygonal models into solids based apps? I talked to Robert Lansdale from Polytrans a couple years ago and he told me it was technically impossible. :screwy:

You can take polygonal models, for example from LightWave, into Inventor using Polytrans - we do it here - but it ends up being just that; a polygon model, with a defined set of points and polygons depicting a surface. Curved surfaces from any polygonal model have facets, as many as you modelled in LightWave, but even though they look great in LightWave, they are still polygons. We use them for placement objects to model around in Inventor, if the part is to be manufactured.

As someone has said - solid modellers use mathematical formulae to describe the outside surface of a solid block of material. This data can then be transcribed to a CAM system. Polygonal modellers, like LightWave, store the data that depicts polygon placement in space as points, and joins them together to form polygons. The more condensed a cluster of points describing a surface, the higher the perceived detail of that surface, but it has its limit. They have a defined resolution, whereas the solid modeller way of things has an infinite resolution. You can convert inbetween using various formats, but there's always compromise between these formats and usually a loss of data and accuracy.

Solid modellers really are fantastic and I am always amazed at what they can do in smoothing the transition from concept to production, and how much time is saved. Saying that, LightWave makes lovely renders of the models we can export from Inventor. Horses for courses.

BH Blackfly 105
02-28-2011, 08:33 AM
I appreciate everyone's reply's. I will look further into checking if my model was "water tight". Maybe there is something more I needed to do to the model, I did verify all my points were welded.

Before I sent the model, I downloaded the SHM Tools plug-in's. It seems to me it only converted my obj file to a STL file. Which was enough for the RPT company to import the model, but not enough to produce a prototype.

This has been an educational lesson though. I have used Autocad since R12 (DOS <-lol!), Mechanical desktop (V 1.0) and tooled around with Solidworks (demo) but I have been intrigued with the creative side of 3D modeling and switched to creating models with less constraints in Lightwave and MAX.

I live in Houston TX. and it is very difficult to find knowledgeable 3D training here. Most everything I have learned, I have learned on my own:grumpy:

Lewis
02-28-2011, 09:32 AM
What I wouldn't use LightWave Modeler for (or _any_ polygonal modeler for that matter) are parts that are to be manufactured for actual real production products. They are simply not designed for this.

SolidWorks and the like should be used, it's what they are intended for.

I agree to this sentiment BUT it's possible from LWM also. I've done Front/Rear bumper and Side skirts for one Tuning company in Canada directly in LWModeler and output to STL and they made molds from that mesh. It was shockingly (to me) precise enough to do it that way without redoing part in Solidworks :D.

BH Blackfly 105
02-28-2011, 09:39 AM
I agree to this sentiment BUT it's possible from LWM also. I've done Front/Rear bumper and Side skirts for one Tuning company in Canada directly in LWModeler and output to STL and they made molds from that mesh. It was shockingly (to me) precise enough to do it that way without redoing part in Solidworks :D.

THATS because your a badass Lewis! :thumbsup:

Your work gives me stiff pants! :D

OnlineRender
02-28-2011, 09:49 AM
THATS because your a badass Lewis! :thumbsup:

Your work gives me stiff pants! :D

+1 on the stiff pants.

Lewis
02-28-2011, 10:14 AM
Heheeh then here is one (watertight) for more stiffness :).

This one was build full SubDs, then freezed at level 4 and triangulated and exported to STL from modeler. Also i noticed that LW plugin was better at exporting/importing STL than Deep exploration which was really weird since DE usually excels and it's much better than LW in other formats so that's kudos to plugin maker then i guess :).

BH Blackfly 105
02-28-2011, 11:03 AM
Heheeh then here is one (watertight) for more stiffness :).

This one was build full SubDs, then freezed at level 4 and triangulated and exported to STL from modeler. Also i noticed that LW plugin was better at exporting/importing STL than Deep exploration which was really weird since DE usually excels and it's much better than LW in other formats so that's kudos to plugin maker then i guess :).

I am looking into this "Freeze" tool now... Maybe THAT is what is causing my file to not be interpreted correctly.

any help is appreciated.

Lewis
02-28-2011, 12:28 PM
I am looking into this "Freeze" tool now... Maybe THAT is what is causing my file to not be interpreted correctly.

any help is appreciated.

Well, freezing is basically subdividing it so you get more polygons since you can't use SubDs and modeling with very hi poly is not really and option since you cant' move/adjust points/edges easily in that dense mesh.

So if your model is SubDs/Subpatches mode (TAB key) just hit CTRL+D to freeze it to "normal polys" and then Triangulate (shift+t) and then export to STL. BTW keep the original file (lower polycount) saved first in case you need to adjust something :).

Titus
02-28-2011, 05:07 PM
Remember to turn off the surface smoothing to see the final model, since you'll get your printed model faceted and not the "rendered".