Difficulty an cutting opening in a model

Practice_Model.skp (448.3 KB)
Hello everyone,

I have attached a model of a gas forge I am planning to make. I’ve made this by creating 2 brick components and them basically copying them and using a combination of move/rotate to position them
into the form you see in the uploaded model.

The holes and squares are not meant to be part of the model. What I wanted to do was be able to cut an opening like what is shown on the top of the forge. I have tried to select the entire bricked structure and draw the circle then use push/pull to cut through but it wont work because each brick is a component and my circle is crossing multiple components.

I then tried to make the entire structure a group and then draw my circle and use push pull to attempt to cut the opening, still no luck.

Then I played around using intersect faces with model and was able to get the circle shape to protrude through the thickness of multiple bricks as shown in the attached model.

I am still not able to cut an opening. I am missing something quite simple but have not been able to figure it out. must be a better workflow or modeling practice that would avoid this issue.

Appreciate any insights you may have.

Thank you,


Hi Rick,

Is this what you are after?

Hi Dave,

In a way yes, I was really just trying to cut an opening like one would do when opening a wall for a window. If i selected an individual brick I was able to easily cut an opening. Thus the reasons for the small holes and squares in each individual brick, i was trying figure out why it was not working.

how did you do it?

All your bricks are instances of the same component. I selected the middle two and made them unique and then the four outside of those were made unique. I also used Flip Along to mirror the components. I made the cylinder into a component. After that I used Trim from Eneroth Solid Tools to trim the bricks with the cylinder. I did explode the two upper level groups so the cylinder and the bricks are in the same context.

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Awesome i have just been playing around with solid tools in an attempt to figure it out.
The problem is that my brick forge was not seen as a solid.

The groups can’t be solid. It’s the bottom level components that are solid.

What was the the problem? The fact that each brick was an instance of the original?

I had tried earlier to select the entire brick structure and make it a component. And tried to draw a circle and use push pull to create the opening. That did not work. however I had not at that time tried solid tools.

Yes. Remember editing one instance of a component results in all the other instances getting the same treatment.

Practice_Model.skp (453.3 KB)
Dave here is my model revised. I made the bricks unique. clicking on them individually indicates that each brick is now a solid. I rebuilt a circular cutter, made it a component and tried using the circle as a cutter into the top 6 center bricks. not working?

You still have a group containing the brick components and the cutter is outside of the group. Either drag the cutter component into the group containing the bricks or explode that outer group. I would explode the outer group because it just makes more work.

You’ve made too many bricks unique. I’ve colored them so you can see.

The ones that are the same color in my first screen shot are instances of the same component. That means when you cut the hole through one of them, the other related components also get the same treatment. So I only needed to trim one blue and one green brick. That’s using Eneroth Solid Tools and not the native Solid Tools. The native ones convert each component they modify into a group and you have to touch each one of the bricks that needs to be cut.

Dave I’m sorry but I am not following this at all. If I started all over this is how i would build this simple brick box. i would make a rectangle 9" x 4.5". make that a component call it full brick, then use push pull and draw it up 2.5". Then draw another rectangle (Square) 4.5" x 4.5" make that a component called half brick and use push pull to draw it up 2.5". I would have only two components and several instances of each. Just like a real brick built box.

I thought the idea in this 3d modeling world was to make anything that repeats a component and use copies of that component to model out your complete structure? All geometry sticks together unless its made a component or a group. I have made it a habit to automatically create components out of every element of a multi component model.

In the model I sent you originally that was exactly how I went about building the model.

Then I would start placing my bricks and making copies as I went along. Eventually I would have my brick box built.

Perhaps this is where I am going a stray?

To cut the openings into each end of the forge I would use the procedure below:

Then I would create another rectangular shape that I would place on the face of the narrow end of the brick box to make the front opening into the forge. Ideally I would use the same rectangular shape to make the back exit hole into the forge.

I obviously don’t understand components copies, instances, groups. The only way I know how to delete a group or component is to explode it. I know I can select a component that was copied and make it unique one at a time, should be a way to select the entire model and make all components unique, not sure how to do that either.


Hey Rick,

I hope that all helped to clarify things. Good to chat with you this evening.

Dave working through the issues with you helped a lot,

Thank you so much


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This is how I would do it. I think using Dave’s technique he mentions here. I would make one of the bricks that would be on the edge of the hole (Dave made these pink in his last screenshot, blue in his first screenshot) unique. Then I would cut the hole template and open that unique brick. Then I would paste in place the hole template inside the brick open for editing. Then I would intersect the portion of the hole template that intersects that brick.

Then I would remove the hole template from that brick and close it. Then move copies of that brick to the locations of the other 3 bricks that are shown blue in Dave’s original screenshot. They would have to be rotated in place.

Then make a brick that he shows green in that original screenshot unique and repeat the same procedure to intersect a hole in it. And then after you have intersected the hole put a copy in the other location that Dave shows a green brick in his original screenshot.

Reading your description sounds like a lot more work than what I showed Rick.

Can I make it easier using 2017 Make which does not have Solid Tools?

There’s always Visuhole if you don’t have solids.

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You could make it easier. Open the brick component for editing, select its top face and use Intersect Faces>With Model. Then Push/Pull the waste. Repeat for the other brick. Instead of rotating the bricks, use Flip Along to create mirrored instances of the components. The curve resulting from the intersection will be exploded but that can be welded and/or the edges soften. I didn’t bother here.

You could also get BoolTools2 and do it even more easily.

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Thanks, I had never used it on components just when I needed to punch through several wall before I made them into a component.

I think I am going to have to use Flip Along more for stuff I am Rotating now. Thanks.