How to really close faces of a plane section cut Object?

Given a 3D Solid printable object , when creating a section with a section plane, how can I really fill the intersection face(s) to obtain a new closed model of its own? not only visually closed (3D printing concern…)
I want to obtain a new real 3D ‘Solid’ object !..

A section plane doesn’t actually cut the object. It’s just an optical illusion. You can draw a rectangle that cuts through the object and use Intersect Faces. Then erase what you don’t want to keep. If you share your .skp file we can give you more guidance.

Thanks Dave.
But I tried with a relatively complex model, and I can’t find an easy way to select at once all the lines and faces located on the same half-space of the rectangle plane…?
Can you say more?
I am a newbe with SU…

How about sharing your model so we can see what you are working with? I expect just dragging a right to left selection around the part you want to highlight and delete will do the job.

dragging a right to left selection ?..
But my section plane is not parallel to anything related to axis…
How can I make such a plane’ horizontal for me’?

I found another solution: using a box instead of a plane (sort of an thick rectangle ! :-), and use the intersection tools BoolTools2 extension to kep the desired intersection!

That doesn’t matter. You need to orbit to the appropriate view.

Your profile says you are using SketchUp Fred (Web). How are you going to use BoolTools2?

No, Dave I am actually in the trial period, with the 2017 Make version…
But what do you mean by orbit to the appropriate view ?
Thanks for your kindness…

Your profile is misleading then. Please fix it.

I could tell you exactly what I mean if you would share your file so I can see what you’ve got and show you.

Ok here it is:
shared on:
Can you open it?

This view works. I used several selection boxes while holding Ctrl.

How is that model 52mb?

Unused components and materials.

Screenshot - 10_2_2020 , 4_25_40 AM
Reduced file size by about 96%.

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?? But when I select, for example, the left vertical line beneath the cut plane, the entire line is slected!
Same for the face: the entire face is selected!
Even with Ctl held…
I missed something

Did you run Intersect Faces to make that angled plane cut through the model? You need to do that before you try erasing the unwanted stuff.

you said run Intersect Faces ???
What’s that? Where is that command?
I am running Make 2017 version, with Pro trial still running for a few days?
or are yountalking of the Web version?

It’s in the context menu. Read:

You should go through the tutorials here and learn about using SketchUp’s features.

Intersect Faces is available in all versions of SketchUp.

You still have yet to correct your profile.

it’s in the context menu

Yes I just found it, sorry !..

Yes, I already tried this morning, to change the version I am using…
but did’nt succeed to acess that precise modification !..

Ok Dave, I succeeded that way, but I had to fill manually a lot of subsequent holes in the cut section…:

  • Is there a predefined command to orient the point of view, in such a way that a given plane -or face- is seen "horizontal " ?
    It would be nice for our ’ right to left drag select’…

-a precision for interested users: before deleting, be sure the intersection lines between model and the cutting plane are not selected…

You wouldn’t have had to fill the holes if you had put the cutting face inside the group with the rest of the geometry.

I think for your odd-angle cutting plane, rotating the group would be the easiest. It’s easy enough to make the selection in several steps so I wouldn’t bother if it was my model but you could certainly do it.

This should go without saying since those edges are required to support the faces. A face can only exist with a closed loop of coplanar edges.