Hi Michael,

Ok I see. Yet I can say that I had experienced it before (one time I had a STL file and it was not water tight but the printing machine was able to print it! However, I have to say I did not discover the mistake until the piece was printed. I think I got lucky!) So, as u mentioned I think it depends on the situation and I can say it is safe to have the 3D model water tight.

Thank you for your support.

Good day Michael.

I finally got some time work back on this.
Since I wanted a 2mm edge so I have projected a closed curve on the model so I could get the desired lines.
And then try to sweep it but I could not get a solid out of it. pls help.

see attached file.

Thank you!

Hi Matadem, the curves to sweep in your attached file are not suitable for making a solid just by themselves. It would be too thin at the ends and be essentially the same as a self intersection in those areas.

To incorporate this into the main model you would sweep to build just a surface and then trim away surrounding areas to make a place to join it in.

I've done that with the model that I attached in the above post here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=10586.14

Was that finished solid that I posted there not suitable for what you need?

- Michael

I did another try here
2 small rectangles at the end a bigger one in the middle which the rails goes into the middle of it...sweep then move this whole solid into my model pushing the other half into my model.
That seems to work but probably not the best or efficient way to do it?

Michael what you shown me was extremely useful, the reason I wanted for a 2mm thickness so it could be easier to sand when fitting the 3d printed item.

Hi Matadem, that looks like a pretty good method. The only thing I'd be a little worried about is if the ends that are just barely skimming over the surface area on the main piece can be booleaned in or not. Surfaces that just barely skim over each other can tend to be difficult for booleans.

But if it worked out ok for you then that's great it was not a problem in this particular case.

- Michael