Gluing face to face failure?

Hi, I want to “glue” face to face 2 solid groups to obtain 1 solid final group (which ultimately is to be 3Dprinted):

  • group1( ’ AV 3D extrudé’) is a wall structure (with wooden doors and windows to be inserted in)
  • group2(’ revet 3D AV’) is a portion of its stone cladding.
    Simplified versions of the groups are joined here (they are declared as true Solid groups by SU and by SolidInspector2)
    gluing rev G to AV extruded.skp (1.8 MB)
    Problem: for this “gluing process” I tried to explode face to face group2 into group1 (or vice versa) but it fails:
    the result is NOT a Solid and lot of faces are inverted!
    I dont understand why?
    Can you help?
    And I didn’t find another method!..?

Outer Shell works.

I understand (haven’t tried it) that leaving it as it is will also work with most 3D printing (slicer) software and when the model has several overlapping or connected solids the slicer will combine them automatically.

No Anssi, in my case OuterShell doesn’t produce a valid ‘solid group’! Why?
(I am using SU Make 2017)
And You mean that a complex model composed of many nested solid groups can be exported as a valid .stl, and printable as such???
Without checking of really glued faces?

In my 2021 version the resulting group reported as solid.
gluing rev G to AV extruded(2).skp (1.9 MB)

As I said, I haven’t tried it myself but have seen references to it (@Box ?)

For my information Anssi, with your 2021 version, can you sucessfully “OuterShell” these 3 solid Groups into one ?
revetement 3D AV offset 4cm G+CD Solid.skp (5.2 MB)

No. The reason is probably that the parts do not quite fit together, leading the Outer Shell tool to create very tiny holes in the shell in places where edge lengths are below Sketchup’s tolerance. Here an example: the corner points of the two adjacent groups don’t quite match.

This might be the result of having Length snapping on.

What do you mean by “lenght snapping on”???
Is it a feature to be ajusted somewhere in SU?
and how did you get those extremely precise dimensions !..?
Thanks a lot Anssi

I don’t much use the Web version. In the Desktop version these adjustments are in Window menu>Model Info>Units.

Here’s the web version.

What is the exact meaning of Length Snapping on?
When set on, while moving a group A does it prevent to attach correctly the moved reference point of A over a refererence point of group B?
…while with the option set off, it will do it precisely?
I thought snapping was snapping to objects!..

Things snap together via inferencing already.
Length Snapping is designed to snap to a specific length, so it’s actually possible for it to miss the point you want by forcing it to a specific length.
Basically it is a setting that is known to cause tiny errors when turned on, and doesn’t really have a very useful benefits.

Ok Box, thanks!

I’ll try to modify and clean up my groups, and to adjust them to each other, without snapping on…
And I’ll tell you if it works…

I have cleaned up and partially redesigned these 2 groups, whith lenght snapping on disabled. The 2 groups are declared solid groups now,
But many pairs of points, which should have been superposed, have coordinates still differing at 0,00001mm scale! And my geometry is too complex to be repaired point after point!
Is there a SU tool/extension which could merge such ‘almost same points’ ?