Merging several surfaces into a part gives different error

oleg_goriunov

Hi
I am trying to merge 4 surfaces together using Boolean Union function.
The problem is that I can successfully merge three out of 4 items, but not the fourth one.
The Boolean function indeed highlights the lines with red which are supposed to be problematic. But I really can't understand what is the problem.

Here is the link to the doc https://cad.onshape.com/documents/d6ef1898cbe78bfe502377d6/w/5c9396ba4ab74ae4bae0801d/e/d6b06a2dfd90111f809ce86f

Prachi

It has been a while since I looked at Simscale but was pretty sure surfaces were not a requirement. Went back to Simscale and found that a solid model could be imported directly from OS. In the sample here, part 1 in studio 5 imported directly. Have not run the simulation but model details are in place.
https://cad.onshape.com/documents/07964c1f8f82cd21f49f477d/w/7d164a9d1caeb961fb2ec834/e/b536af277e55d8944818443e

lana

Surface restrictor can not be merged with Horizontal Pipe because such merge would create non-manifold geometry. 

oleg_goriunov

This is how it looks 

EvanReese

What are you wanting to happen with that surface called "Surface restrictor"? it's completely inside the other parts, so even if this worked I'd expect it to just disappear

Prachi

A little confused at what your trying to accomplish! Perhaps a description of what end result is intended. There seems to be a lot of extra steps involved in keeping and closing surfaces. The Boolean you are working with includes surfaces that used 'add' when created.

oleg_goriunov

Hi Evan, Glen,
Thank you for having a look at the doc!

The whole thing is a ventilation pipe with a box attached to it. The restrictor is supposed to re-direct part of the airflow (coming from bottom-up) into the box.

I am creating this model to import it into a physical processes simulator (called simscale). Simscale requires all the components to be one single part.

The restrictor that is inside the main part is created by extrusion from a line limited by the side surfaces of the box and then split by the horizontal pipe.
(Alternative variant that I used to make was to create this restrictor by extruding a line limited by the part (three united surfaces: box+horzontal pie + vertical pipe).

Keeping in mind that I created the restrictor by extrusion limited by the shape of the surrounded objects, I expect it to coincide in size with the volume of the surrounding objects (box + pipes). 

My final aim to to make the whole thing being a single part. (preferable keeping it all surfaces, not transforming (thickening) into a solid. But if surfaces approach won't work, I'd have to go solid).

P.S. For some very strange reason I am unable to post a new comment for a few hours already (like it is under review)

lana

@oleg_shilovitsky
You might find it easier to build everything except for "Surface restrictor" as a solid and either hollow it or offset surface with 0 offset, if you want the final model to be a surface.
In your model the Boolean operation should succeed if Surface restrictor is not selected in it.  It can not be merged with Horizontal Pipe. 

Prachi

Got a little closer with less and I think simpler features. Still will not let me boolean the restrictor into a single surface.
https://cad.onshape.com/documents/07964c1f8f82cd21f49f477d/w/7d164a9d1caeb961fb2ec834/e/b536af277e55d8944818443e

oleg_goriunov

That's the point - it lets me unite 3 out of 4 surfaces (except the restrictor) into a single part. but that's not enough.
I can't figure out how to make all the 4 surfaces a single part.

Any ideas?

Prachi

It has been a while since I looked at Simscale but was pretty sure surfaces were not a requirement. Went back to Simscale and found that a solid model could be imported directly from OS. In the sample here, part 1 in studio 5 imported directly. Have not run the simulation but model details are in place.
https://cad.onshape.com/documents/07964c1f8f82cd21f49f477d/w/7d164a9d1caeb961fb2ec834/e/b536af277e55d8944818443e

Prachi

lana

Surface restrictor can not be merged with Horizontal Pipe because such merge would create non-manifold geometry. 

oleg_goriunov

Glen,
Thanks! Your approach (turning it into solid) worked! Thank you also for the model!