Question about creating precisely holes in big object to fit small objects

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Hi, I am a student, and I have been using Shapr3D with basic beginner-level workflows to create models such as ships and weapon equipment for use in video game projects.

Previously, when I wanted to create a hole in a large body that precisely fits several smaller bodies inside it, I used the following workflow (example: placing VLS modules into a ship hull):

Directly performing Boolean → Subtract (large body minus the small bodies) would result in the error:

“Operation failed because it would create a non-manifold body.”

So instead, I did this:

  1. I placed the smaller bodies on top of the larger body (they are touching, but not intersecting).

  2. I created a rectangular sketch on the surface of the large body.

  3. I extruded the rectangle downward.
    In previous versions of Shapr3D, this extrusion would leave behind protrusions inside the rectangle, each exactly matching the footprint of the smaller bodies.

  4. Then, I would extrude the protrusions downward to the correct depth, and extrude the surrounding rectangle back upward.
    This resulted in a precise hole that fits the smaller bodies perfectly, without affecting or modifying the smaller bodies themselves.

    屏幕截图 2025-11-09 220500
    屏幕截图 2025-11-09 2205001920×1135 295 KB

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    image1920×1297 300 KB

However, this workflow no longer works in recent versions.

Now, when I extrude the rectangular sketch downward, the extrusion no longer preserves protrusions around the smaller bodies.
If I extrude upward, the extrusion will directly cut into or remove part of the smaller bodies, which did not happen before.

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image1920×1138 357 KB

Steps to Reproduce:

  1. Place several small solid cubes touching the top surface of a larger solid cube (Fits snugly but does not intersect).
  2. Create a rectangular sketch on the surface of the large cube.
  3. Extrude the rectangle sketch downward.

Expected Result:
The extrusion should leave protrusions that match the footprint of the smaller cubes.

Actual Result:
The extrusion does not preserve the shape of the smaller cubes, and upward extrusion will remove parts of them.

Question:
Has Shapr3D changed how extruded sketches interact with nearby bodies in recent updates?
If so, where can I find a new tutorial or guide for creating precisely fitted holes around multiple separate bodies?

Thank you.

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I don’t remember behavior like the one you’re describing. If you union all the objects, then it will behave like you said. In your case, you can always project the small pieces onto the sketch, and then it will act as you intend.

Nevertheless, I’m curious why, when you use a simpler method, you get: “Operation failed because it would create a non-manifold body.” Could you share one of your models and let me try to figure out what’s going on there?

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Hi, this is models link, if that link dosen’t work, please reply me