New to Blender, tried to search for this issue but I think because I am new I am missing something. I am 3D printing my life sized skull in resin and want to recreate the surgical plates as well, only I want them to be metal. I found a place that can print metal (the manufacturer of the plates will not sell them to me) BUT I am having issues.

I am using images from a PDF of the companies catalog for sizing/scaling, which I created as an AI file, then converted to SVG for import into Blender. I was able to set the plates to the correct thickness, so they actually look decent.

To get the plates to look more like (see below), I need to do the following:

  1. Use boolean modifier to cut cylinder indents into the plates
  2. Bevel edges of the plates


What am I doing wrong for the first thing?? Is it something to do with my layers? It keeps adding my cylinder to the plates!!! SOS!! Here is my Blend file.

I have also included an STL of the plates that I already built from the scan of my head... pros of that are that I do not need to hand bend anything, but I am not happy with the way they look.

enter image description here

EDIT: The end product should look something like this (I don't have this big large one but anyway...) enter image description here

EDIT 2: This is all that I need to do, forget I said anything about beveling because I think it is causing you confusion (I will put screws here, you wouldn't see a bevel anyway). The bevel I mentioned for step 2 would be for the OUTSIDE edges of the plates but I haven't gotten to that step. I've done like you've showed and made a shape for boolean subtraction but for some reason it is still not working on my existing shape. :( enter image description here


2 Answers 2


The problem I see in your file is a lot of messy geometry, if you enable Face Orientation in the Overlays for example almost every face shows a red and blue artifacts pattern because there are loads of overlapping faces which are really hard to clean up automatically. The best would be to just select the outlining edges and create completely new faces.

Okay, now technically this question turns out to be two questions which should be asked separately: 1. How to clean up this messy geometry? and 2. how to create the chamfer screwholes?

How to clean up the messy geometry?
  1. In Edit Mode go into Wireframe mode or enable X-Ray to make sure you can select all hidden vertices/edges. Make sure you are in Edge Select mode (press 2) and go into side view Numpad 3. Then box select only the bottom row of edges by dragging your mouse over them.

    select bottom edges

    This is how it should look like afterwards:

    selected edges

  2. Looking at it from below to see what is going on next: with all the edges selected, go to the Select menu and choose Select Loops > Select Boundary Loops.

    select boundary loops

  3. Now only the outlining edges are selected. Now these need to be separated from the rest of the mesh. To not destroy the original, duplicate the edges with Shift+D and immediate right-click so that they stay in the original position. Then press P > Separate > Selection.

    separate selection

  4. Now you can go back into Object Mode and hide the original object by either selecting it and then H to hide, or you select the new object and go into Local view by pressing Numpad /.

    edge object

  5. Tab in Edit Mode. As you can see in the previous screenshot, I have enabled the Statistics overlay which shows that there are 10,008 vertices. Apart from duplicates I don't think that much is necessary. So select all with A, then hit M > Merge > By Distance. The default Merge Distance value of 0.0001 removes 20 vertices (they are definitely duplicates), but I reduced the number even more by setting a distance of 0.001 which removes 1,065 vertices. This is of course my personal taste, but you have to at least get rid of those 20 duplicates.

    merging by distance

  6. The next step is also optional, I tried to reduce the vertex even further: I press X > Limited Dissolve and left the Max Angle at the default value of 5°, now the mesh is down to 5,282 vertices.

    limited dissolve

  7. Now come the annoying tedious parts of cleaning up. To create new faces, first of all the inner circles which will become the holes need to be connected to the outline. A face cannot have an unconnected hole, this means all holes need two edges that connect them with the outline. To make those connections, select a vertex on an inner circle and one vertex close to it on the outline edge, then press F to connect them.

    connect vertices

  8. This has to be repeated until all inner circles are connected by at least two edges. It is okay if those edges just connect to another circle, as long as in the end they are all connected to the outline. Unfortunately I don't know a better, easier way to do this - maybe someone else does.

    all edges connected

  9. Now you can select all edges/vertices formed by one connection to the enxt connection. In my case, the way I created the edges, this is one half of the shape.

    select boundary loop

    Depending on how you connect the vertices or how the shape of the part is, this can also be like this... how you do it is quite arbitrary:

    other boundary selection

  10. With this selection you can now create a new face by pressing F to fill it. Sometimes there can be problems if it forms a concave face, maybe you then have to select less vertices to make smaller faces.

    filled face

  11. Then you can select the remaining vertices and press F again to create the rest of the shape. You should enable Face Orientation in the Overlays to see if the faces are oriented correctly. If they are blue, the face normals are oriented correct. If they are red or some blue, some red select them all and either use Shift+N > Recalculate Normals to change them or if that doesn't help you can use Alt+N > Flip to switch faces that are still red.

    face orientation

  12. At last, with the faces selected, press E to extrude them upwards. You can either do it by eye or enter a value or maybe snap it to the height of the original part (if you make it visible again if it's hidden or return from Local view with Numpad /).

    extrude faces

How to create those chamfer screwholes?

When you cleaned up the geometry like described above, it should be no problem to do it with the Boolean modifier. But anyway, here is an alternative method to do it:

  1. Select the edge loop around the hole.

    select edge loop

  2. Use the tool Rip Vertices And Fill and immediately Scale to create an outer ring. To do this, press Alt+V, S and drag to the desired size, left-click to confirm.

    rip vertices and fill, scale

  3. Select the ring of faces around the hole, then press Alt+E > Extrude Manifold.

    extrude manifold

  4. This way you can extrude the faces downwards without creating duplicate geometry, left-click to confirm.

    extrude faces downwards

  5. Now select the edge loop around the hole again.

    select edge loop again

  6. Press Ctrl+B to bevel the edge to create a chamfer (scroll mouse wheel if the bevel has more than one segment).

    bevel edges

  7. If you don't want a small step on top of the chamfer, you can bevel the edge until it reaches the border. To make sure it doesn't overlap by going too far, you can hit C while beveling, this toggles Clamp Overlap on/off.

    bevel clamped

  8. If you've done it like this with the bevel reaching the outer edge, to remove duplicate vertices select all with A, then press M > Merge > By Distance.

    merge by distance

By the way: all the steps I described above also work on multiple holes simultaneously if you make sure that the Transform Pivot Point is set to Individual Origins:

pivot point individual origins

  • $\begingroup$ This is literally SO helpful., thank you THANK YOU! I am having slight issues with the filling step (you have to manually select the edges, correct? And I assume this is why you wanted to decrease the vertices as much as possible?? To make it cleaner to work with?) I think I will redo the Illustrator file without the holes to begin with (idk why they aren't even round...), then do as you said to get them 3D because I did follow that quite easily!! :) Then hopefully the boolean method works for my holes, though, I would like to try to learn the 2nd way too. $\endgroup$
    – Connor
    Commented Feb 22, 2023 at 17:18
  • $\begingroup$ @Connor Yes, most of the edges have to be selected manually. Of course you can use Circle Select (C) or things like Pick Shortest Path (Ctrl + left-click), but it's still a lot to do. Learning the second method will definitely be worth a try, since everything you learn might be helpful in future projects. $\endgroup$ Commented Feb 22, 2023 at 17:28

first make it look like this one clean and okay to work with enter image description here

now select the edge of the circle and press ctrl + B to add a chamfer like this enter image description here

now all you need to do is to press ctrl+R on this face to make a loopcut select the top of the loop cut faces and scale the z axis to 0 so that it will be flat

enter image description here

to do that all you need to do is press s and then z and then 0 and now you have yourself a ring around your circle enter image description here now select everything and press gthen z and drag it down so u can have a hole enter image description here another easier way is to make a cylinder like this one and just intersect it with your 3d model enter image description here

here is the boolean file you could use and change here is the file

  • $\begingroup$ Yes I know the geometry is a mess haha but before I fix it nicely I want to make sure I will be able to get my details (otherwise I will print the STL I already created which will not print as nicely but will work): What I need is the circle to be indented into the existing mesh plates. See how I had It only partially into the surface? It won't let me attach another picture so let me edit the original post. $\endgroup$
    – Connor
    Commented Feb 21, 2023 at 16:46
  • $\begingroup$ if you had a final product image it would help alot $\endgroup$
    – AHIVO
    Commented Feb 21, 2023 at 16:54
  • $\begingroup$ check now, I added it :) Thank you so much!! $\endgroup$
    – Connor
    Commented Feb 21, 2023 at 16:58
  • $\begingroup$ edited my post, see if it helps! $\endgroup$
    – AHIVO
    Commented Feb 21, 2023 at 17:27
  • $\begingroup$ unfortunately the whole boolean thing is just not seeming to work, I edited again.... thank you for your time!!! Not an easy program to self teach... Do my layers have anything to do with it?? $\endgroup$
    – Connor
    Commented Feb 21, 2023 at 19:16

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