View Full Version : making my model "waterproof"

03-31-2005, 03:31 AM
Hello all.

For a project on my university I am developing a concept cycling computer which will help the amateur cyclist to effectively use heartrate information during training.

I have chosen Lightwave to model and render my concept, and these are some of the latest renders:

As I am happy with the results (once again), the next step of my project is to make a rapid prototype of this model. My model is built in lw using a number of layers, this resulting in different objects overlapping each other (surfaces within surfaces). Heres my problem: To make a rapid prototype I need the model to be waterproof meaning that there are seamless connections between surfaces and that there are no shells (surfaces within surfaces). Ive tried using boolean subtract, but dont get the right result. When the model is waterproof and has no more shells than I will convert it to the .stl format so that it can be rapid prototyped. Here are a couple of screenshots, I can post more on request.

Any help is much appreciated.


03-31-2005, 04:12 AM
I know that's not what you want to hear, but freezing, booleaning and manually welding will most likely be your only reliable option at this point. Another option might be (but that's a big "if") to get your mesh inside a CAD/ analytical geometry builder tool and use their "wrap" and "rebuild shell" tools. Dunno if that works and is good enough, but i know that such tools exist. Along those lines you could also try to "wrap" your object using cloth dynamics. Simulation will be slow due to the high resolution required, but once you have a lower and a top half frozen using "save transformed" it should not be too difficult to merge them in a clean and usable fashion.


03-31-2005, 04:36 AM
Thanks for your fast reply Mylenium

I have already frozen this model, and tried to use the boolean subtract function, but it isnt working as it should do. What I am trying to say is that if the shapes become more and more complex, surfaces are deleted or added which are not intended to be deleted. I can post a few shots here soon, to show you what I mean.

03-31-2005, 04:52 AM
Connecting two surfaces seamless:

the number of point is different on each surface, so its not "waterproof"


Polygons behind other polygons may be deleted (surfaces under surfaces)
Marked in yellow here.


03-31-2005, 10:09 AM
I think you are looking for an easy solution where there is none...

a) LW's booleans aren't very sophisticated and clean, so it will always create unnecessary vertices and remaining polygons. You always need to remove those manually. That's ugly and time consuming, but there's no way around it.

b) Triangulate (triple) your geometry before doing booleans. This improves things a bit.

c) You need to copy your layers to do multiple cuts e.g. you need to cut your tube with the main body but on another layer as well. This will give you at leat some points to merge your meshes once you have copied them to the same layer.

d) Get rid of those large n-gons. Triple them or add geometry by beveling them (inset only) without changing the flow of your geometry. I also noticed that you have a lot of triangular polygons already in your SubD version which also disturb the flow. Try to fix them as well. They create sharp pinches that are not good for booleans as well.


03-31-2005, 01:00 PM
I've had to do something very similar, but i actually used 3dsMAX because it has an STL check button hidden away somewhere. I wouldn't normally suggest to use any other software, but you could try it out if you get really stuck. Upon performing the STL check it highlights all the edges in red so you can see which ones need to be dealt with.

I'm also not 100% sure, but wouldn't a boolean union work rather than a subtract??

Try it and see if it works? Also after boolean operations you HAVE to merge points to make sure there aren't any duplicate points occupying the same space.

Good luck

04-01-2005, 08:22 AM
ok thanks for all the tips, guess i'll have to put in some extra work.

still have one noob question: what is an n-gon?

04-01-2005, 01:16 PM
An n-gon is a polygon with more than 4 sides/edges. Lightwave doesn't support them (as yet) but keeping to four-sided polys is always the best bet anyway. N-gons are supported by a few packages now, so i'm sure LW will be doing that soon!

04-01-2005, 07:31 PM
I think he means subD support - they are ok when not subdivided I thought, I dont usually have problems with eps or text objects and they have loads of points

04-01-2005, 09:10 PM
Your situation and needs are similar to mine. I make lots of models for rapid prototyping. Here are some tips from my experience that may help you.

As far as 3D printing and rapid prototyping. I have been using 3D Art to Part (http://www.3darttopart.com/index.php). I have checked out other companies. But 3D Art to Part (http://www.3darttopart.com/index.php) seems to know what they are doing. Especially with lightwave objects. I have been sending them my lightwave model files as is, and they have had no problem in printing them for me. And yes. They can fix holes with no extra charge.

You can also do a search for <<holes>> on www.flay.com. There are several plug-ins that you can download. The one that stands out to me is Cap Hole Studio (http://www.wtools3d.com/index.php?menu=full&strana=caphole) .

One more link that may interest you. <<scaling>> (http://vbulletin.newtek.com/showthread.php?t=30899)

If you find a solution to your situation. Can you pass it on to me? Thanks in advance

3D Art to Part (http://www.3darttopart.com/index.php)
Cap Hole Studio (http://www.wtools3d.com/index.php?menu=full&strana=caphole)


04-01-2005, 09:25 PM
Sorry, but I forgot one other link that may help you.

It is Rhino 3D (http://www.rhino3d.com/) . Download the demo (http://download.mcneel.com/rhino/3.0/eval/default.asp) . It is good for 25 free saves. It can convert your lightwave objects to what ever you need to sent to a rapid prototyper.

I hope this helps you.


04-01-2005, 09:26 PM
Sorry, but I forgot one other link that may help you.

It is Rhino 3D (http://www.rhino3d.com/) . Download the demo (http://download.mcneel.com/rhino/3.0/eval/default.asp) . It is good for 25 free saves.
It can convert your lightwave objects to what ever you need to send to a rapid prototyper.

I hope this helps you.

P.S. Sorry, I do not know how my message got repeated.
I just tried to re-edit or fix a link