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sublimationman
02-03-2014, 10:04 PM
This is for a 3D print so the mesh needs to be perfect, water tight as they say (or manifold).

What is the proper way to merge these? They are 3 triangles on 3 separate layers. I need to run groves into the bottom with boolean. If I just place them on the same layer it gets weird where everything overlaps. Should I individually boolean subtract each from the other, or something like this?


I run into this dilemma more and more now that I have a 3D printer, if it were just for looks I could just leave them as is but I need functionality and the mesh needs to be cleaner.

Thanks!

geo_n
02-03-2014, 10:18 PM
I would import these into 3dcoat as voxels. Add details then autorepo.

sublimationman
02-03-2014, 10:30 PM
But i don't have 3D coat.

shrox
02-03-2014, 10:34 PM
That looks really easy, use knife to slice out the various pieces, then add a few points if necessary, then merge the overlapping points.

geo_n
02-03-2014, 10:46 PM
Old fashioned rebuild. Kill (k) all polys leaving only the points. Rebuild from points.

JoePoe
02-03-2014, 11:29 PM
What does a 3d print mesh need to be? Quads? Tris?
...this is neither.... has ngons. But, hey... it's not subD, just triple.

I just did what you were thinking.... two boolean unions.
I put some grooves in the bottom after, but the un-grooved union is in layer 1.

sublimationman
02-04-2014, 03:50 AM
Weird, when I do the boolean Union I loose polygons.

And yes they need to be tri's but saving as stl format does that anyway.

sublimationman
02-04-2014, 04:18 AM
Well I found out something weird. You see all my triangles were flat on the ground and boolean did not like them being in the same plane. I raised one up 10um and then the Union worked, merged points and it seems good.

Now, my groves form an X twice (unlike yours) so we shall see how that goes but time for bed now.

erikals
02-04-2014, 10:38 AM
yep, you need to offset it in order for the boolean to work,
then flatten the bottom polys if needed...

sublimationman
02-04-2014, 02:33 PM
Still learning stuff in Lightwave since V1.5

meatycheesyboy
02-04-2014, 02:47 PM
Old fashioned rebuild. Kill (k) all polys leaving only the points. Rebuild from points.

This is how I'd do it. No need to over-complicate things.

spherical
02-04-2014, 04:12 PM
What does a 3d print mesh need to be? Quads? Tris?
...this is neither.... has ngons. But, hey... it's not subD, just triple.

You can model any way you like, but the final model, that will go to the slicer as an STL file, should be all tris. I usually get the shape I want, triple manually (not relying on the STL exporter to think it knows what it's doing) and either save as a different LWO and then use a dedicated format translator or sometimes use the STL exporter. This leaves my source model as is for later editing.

spherical
02-04-2014, 04:28 PM
Well I found out something weird. You see all my triangles were flat on the ground and boolean did not like them being in the same plane.

A cutter cannot divide a point. It is a point. It has no size to divide. Likewise a poly edge-on. It has no thickness. This is what is trying to happen when polys are on the same plane and there is no overlap, or a cutter goes through a mesh at any angle and strikes a point; you'll either get garbage or the Boolean tool will wig out and crash or do nothing. Depends upon how it feels that day.


I raised one up 10um and then the Union worked, merged points and it seems good.

I was going to suggest duplicating the center wedge and drop the bottom poly down. Then use it as the cutter on the other two. (May work to do them both at the same time, may not.) Then weld points on the dropped down poly to their upper counterparts; creating the flat plane again.

erikals
02-05-2014, 12:21 AM
some ideas >


http://youtu.be/eIZYxlF651Q

Snosrap
02-06-2014, 12:24 PM
erikals - Do you have a life? :)

erikals
02-06-2014, 03:47 PM
not yet... http://erikalstad.com/backup/misc.php_files/wink.gif

erikals
10-03-2015, 02:20 PM
hi, bit bumping here, but thought i'd share as i found a better approach...


https://www.youtube.com/watch?v=95mIUpv13Yg

erikals
10-03-2015, 02:59 PM
and the standard "u-feel-lucky" approach ...


https://www.youtube.com/watch?v=q69YmwnVxCU

jeric_synergy
10-04-2015, 01:11 AM
I'm not sure what you're getting at here. FWIW, I cut&pasted the middle one, put the other 2 in the foreground, the middle in the background, and did a standard Boolean:Union, no worries.

Snosrap
10-04-2015, 07:41 AM
I'm not sure what you're getting at here. FWIW, I cut&pasted the middle one, put the other 2 in the foreground, the middle in the background, and did a standard Boolean:Union, no worries.

erikals loves to dig into these types of things. I think he's a real asset to the community and he usually gets my brain thinking in different ways.