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As this is a 3D print I need some depth with my walls so simply creating an end face would not do. So I am trying to perform a triangular extrusion between the two objects expecting a solid block to be made between said two objects. Instead what I get is what looks like an inward fill leaving zero faces and an open end.

I have tried swapping the normals around on the triangle face but to no avail. All the online searches I found focus on how to create an inward extrusion or to perform a merge at distance to confirm there are no overlapping vertices but the extrusion works along its normal, its just the wrong type of extrusion.

enter image description here

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  • $\begingroup$ Hi. You might have better luck getting an answer if you could upload your .blend file or at least some portion of it with this end of the object to: blend-exchange.com $\endgroup$
    – curious_1
    Commented May 23, 2023 at 23:28
  • $\begingroup$ Yes of course. I have used Blend-Exchange which by the read of it seems to be the best way to host the file. If this is not desirable can someone let me know. $\endgroup$
    – GrumpyDave
    Commented May 24, 2023 at 0:10
  • $\begingroup$ Will selecting the edges of the triangle pointed to by the bottom arrow in the image above and then pressing the F key to put a face there give you what you want? I don't know why it extrudes like that. $\endgroup$
    – curious_1
    Commented May 24, 2023 at 3:02
  • $\begingroup$ That would absolutely fix the visuals, however I need wall depth and this maintains two zero depth faces (top two edges running along the top) instead of a solid triangle from one end to the other. I think the problem is my workflow, I suspect outward extruding is for external faces and not between two faces so I think I may need to rethink how to create this. $\endgroup$
    – GrumpyDave
    Commented May 24, 2023 at 3:31
  • $\begingroup$ If it is any help to you, look at the top edges in vertex mode. You will see a vertex on each edge 5 "sockets" in from the end. Dissolve the verts and that gets rid of one problem. I tried making a triangle as a separate object and extruding it and joining that object to the 6 x Strips object, but it still leaves 1 zero face on the new triangle. $\endgroup$
    – curious_1
    Commented May 24, 2023 at 7:16

1 Answer 1

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Since you have solved the problem, if what I do also solves it, maybe there will be something here that will be useful in the future.

Based on you mentioning zero faces, I'm assuming that you are using the Blender included addon 3D Print Toolbox to check the object. I am using it for this.

Checking with the toolbox gives this result. I have used Shift->Z to better show the zero faces:

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Going into vertex select mode, one sees the edges have vertices subdividing them:

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Selecting those vertices and dissolving them gives this result in 3D Print Toolbox:

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Select the top edge of the end triangle and delete it:

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In vertex select mode, select the vertex at the bottom of the vee and using the method in the image, move the 3D Cursor to the vertex:

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Click on the View Tab in the N Panel and check the 3D Cursor Rotation. Set all rotation axes to 0:

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In Object mode I used the Blender included addon Add Mesh: Extra Ojects to add a single vertex:

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With the vertex selected and vertex snapping turned on, draw a new triangle. To avoid having a duplicate vertex, turn on Auto Merge Vertices. Or, after drawing the triangle, use Merge By Distance to get rid of the extra vertex. Then put a face in it:

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I'm not sure if you want the entire length filled, or just some length at each end. In the first case extrude the triangle to the other end. You will then need to flip normals:

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Go to Object mode, select the triangle object first and the 6 x Strips object second. CTRL->J to join them:

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The 3D Print Toolbox gives this result:

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If only some length at each end, extrude the triangle that length and flip normals. In Object mode with vertex snapping turned on, Shift->D->X to move the duplicate triangle to the other end. Do the same procedure as mentioned to join the objects. The result:

enter image description here

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  • $\begingroup$ Yes that works great. Extruding is far more complicated than I thought and I have to get used to check normals whenever I create a 2d face. That auto-merge option is a great piece of advice. I have been creating duplicate vertices all over the place. Thanks for the super-human effort $\endgroup$
    – GrumpyDave
    Commented May 25, 2023 at 5:01
  • $\begingroup$ @GrumpyDave I'm glad I could help. In the 5th image from the bottom where I show the auto merge turned on, to the right of that is an Options dropdown. You may find sometime that the vertex is merging not where you want it to. You can adjust that by lowering the threshold value, maybe to a very small amount. Continued... $\endgroup$
    – curious_1
    Commented May 25, 2023 at 5:43
  • $\begingroup$ ... Any time you start to extrude a vertex and then hit ESC, you will duplicate that vertex. You can either CTRL->Z to undo that, or after you've finished extruding, do merge by distance to clean things up. You can also set this merge distance in the popup window that will appear at the bottom left of the viewport. $\endgroup$
    – curious_1
    Commented May 25, 2023 at 5:44
  • $\begingroup$ So, it seems there is also another workflow I found which can help. I found the solidy modifier but found you can also use solidify on an number of active faces, I can also use move axis if I want to snap. Soooo much to learn. $\endgroup$
    – GrumpyDave
    Commented May 25, 2023 at 6:24

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