How do you Select faces/vertices based on shape of other object?

So I got the solution. It was present in my previous post.

I am leaving a link to the post.

Tl;dr - use the knife project action and the other object needs to have faces and a simple edge loop will not work!

Hi guys. Need a help!

I want to select all the vertices or faces inside that edge loop. Both are different objects. Basically, the selected object should project a selection on the other object.

IIRC, this type of selection is used while making grilles in car modelling. But unfortunately, searching didn’t bring many good results.


I can manually select the faces inside by eyeballing it with the box and circular selection but that’s too time-consuming.

I am pretty sure there’s a shortcut to doing so. I just don’t remember the exact method.

Hoping for a quick reply and thanks in advance.

There is no selection method like that, unless some addon does it. You could use the edges as a cutter with knife project tool.

Edit: actually, I think the pieces aren’t connected so can’t use knife project for that. Freaking cropshots

you’ll have to use the circle selection tool/box select tool and manually do that. Time consuming, but the more time you put into something the better it’ll likely turn out :stuck_out_tongue:

Manual working is so difficult. Guess that’s the only option left if I cannot get the exact method.

I made models of some cars 2 years ago and I remember using this kind of method extensively for making grilles for the bumpers and other areas. But I was away from blender for quite some time now and I actually forgot how I did it.

It could be some add-ons. I don’t remember. It had to do with something like selecting one object and then second, and pressing some buttons and behold, you have a perfectly masked selection.

Got the solution. So apparently a pseudo-selection method exists. It was knife project all along. Here’s the link to the discussion.

problem with knife cut and select is that it will select all the inside
but also cut your original mesh and add verts

so not equivalent to select part of your mesh !

happy bl

But knife project tool does not create cuts. it just selects.

This looks like a perfect example of how important it is to provide full context and use the right terminology when asking questions. You asked how to select and did not tell anybody anything about what your goal was or what you were doing. So people are talking precisely about what you asked. It just so happens that what you need is a totally different thing and it is impossible for anybody trying to help you to know that. Anybody here could have advised you to use the Boolean modifier after giving the edge loop some volume by filing it(f with all selected) and extruding(e) in the first place because it works with an object made of separate islands and gets the exact results shown in the thread you linked to. All you needed was to describe the purpose of the selection you were talking about and also what kind of object you were modelling. Tell everybody a bit more about your situation the next time you ask something, I bet you will see it’s much faster an efficient that way.

Yes brother. It was my bad. Should have been more clear. But this project is completely different than the one I linked. And most importantly, if I knew boolean modifier’s purpose here, I would have given clearer details.

Thanks for letting me know about the boolean method. Learned something new.