I would like to extend the raised ridge along all the length of leg to go all the way around the front (the round bit with 5 holes in it) and join up with the edge on the other side of the leg again.

My first thoughts were something along the lines of selecting the vertices around the front, shrinking the selection to the width of the edge then extruding it but I'm unsure how to accomplish this with my limited Blender skills.

Any pointers in the right direction would be much appreciated.

enter image description here

enter image description here

STL file of the design in the link bellow


  • $\begingroup$ It all depends on the topology. You may have to re-model it using the original as reference. Include a wireframe for a more helpful answer :P $\endgroup$ – VRM Apr 22 '16 at 16:34

If you can live with the awful topology of the mesh here are the rough steps to accomplish modeling that ridge:

Lets start by sanitizing the mesh first

  1. Select these vertex and move your 3D cursor there with Shift + S Cursor to selected


  1. Exit edit mode and move the center of the object to the cursor with Shift + Ctrl + Alt + S > Origin to 3D cursor
  2. Now that your Arm object has a sane center move it to the scene's origin (coordinate 0,0,0)

Now lets make the object symmetrical

  1. Add a vertical plane at the object/scene origin

enter image description here

  1. Scale it so it reaches the whole object

  2. With both selected enter edit mode on the arm object, and in top view use the operator Knife Project to cut your whole geometry in half. Use the option cut through for best results

  3. Now delete half of the mesh, making sure you delete all the small faces along the symetry axis

enter image description here

  1. Now you can add a mirror modifier to the object so you only have to deal with half of the mesh and model part of it. Blender will take care of the symmetry

Modeling the ridge

  1. Now delete this part of the mesh

Deleting Deleted

  1. Select the border of the round part an duplicate it with Shift + D


  1. Scale in inwards towards the cursor by pressing . then S to scale and Shift + Z to keep it from scaling in Z direction

  2. Separate the scaled edges into a new object with P

  3. Now use the Knife Project as described above with the plane to cut it into the mesh

  4. Enter edit mode again and you can select these faces

Border faces

  1. Extrude them until they reach the desired height


  1. Exit edit mode and add a new plane at exactly the height of the top of the round part

Knife project

  1. Scale it so it covers the whole object and use knife project again to cur a new loop on the mesh

New loop

  1. You can now bridge these edges with F and start closing your geometry

enter image description here

  1. Extrude the sides up. Make sure the surrounding vertex are vertically aligned with the remaining ones so they lign up

enter image description here

  1. Done


  • $\begingroup$ Thanks for the detailed answer, Duarte. I've not tried it but the end result is exactly what I'm after. $\endgroup$ – drjeep Apr 23 '16 at 9:59
  • $\begingroup$ FYI couldn't get step 6 to work, cut using boolean modifier instead. $\endgroup$ – drjeep Apr 23 '16 at 14:20
  • $\begingroup$ Yeah knife project can be a bit finicky at times. I did forget to mention you have to manually delete the remaining faces afterwards. Edited to reflect that $\endgroup$ – Duarte Farrajota Ramos Apr 23 '16 at 14:38

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