AnsweredAssumed Answered

Offset surfaces and generating solids

Question asked by Salted Fish on Oct 26, 2018
Latest reply on Oct 29, 2018 by Doug Seibel

Hello all.


I am working as an apprentice mold maker, and am trying to generate a solid to use as a template for the electrode on my sinker. To do this, I want to use the model I received from the customer, select the relevant surfaces, offset them by the orbit amount, then construct a solid with the offset surfaces that I can then use to generate toolpaths on the mill. I'll explain the workflow as best I can along with the questions I have below.


To start with, I'd like to use the "Offset Surface" to generate faces offset by the desired orbit amount. The geometry at this stage is often very complex, involving many angles, fillets and disparate faces numbering in the hundreds. To progress past this point, I will usually change the view to "Front" and then click-and-drag to select all the visible faces, then rotate the camera to find and select any that didn't get selected.

  • My only problem here is the offset amount -- can anyone elaborate on what parameters restrict the distance? For my current project, I wanted to use an offset of about .005", but Solidworks was unable to make that work. However, .004" worked. Why is this? Is there a radius somewhere that at .005" offset would disappear? What's going on behind the scenes that Solidworks isn't telling me?


After this point, I suppress the original part solid, leaving only the offset surfaces floating in space. Now, I'd like to construct geometry around the boundaries of the offset surface to turn it into an actual fully contained solid. Or perhaps "enclosed" solid is a better term. Specifically, the electrode will be machined out of a rectangular block of copper, and I would like to simulate the dimensions of that block at this stage. Maybe one way to visualize it is that right now, I have the front face of the block, but none of the others. I'd like to draw those other faces in so that I know how big of a block I'll need, and to import a complete solid into MasterCAM for toolpath generation.

  • What I'm trying to do is turn on the visibility of the Front plane, create a sketch, and then "Convert Entities" to create sketch lines where the Front plane and the offset surfaces intersect. However, I have to select each line individually, and as the offset surface is extremely complex, this would take a long time and there must be a better way to do it.
  • My hope is that once I've created sketch geometry where the offset surfaces intersect the sketch plane, I can then use the Line tool to complete a bounding rectangle around the surface and then, from there, exit the sketch and extrude away from the offset surfaces to make the rest of the electrode.


I understand it's difficult to visualize, and I am not able to share pictures of what I am doing due to copyright issues. I'll try to give an example:


Look at your computer mouse. Imagine having a solid of it in Solidworks. Now offset the upper surface, the one your hand rests on, but away from your palm. Suppress the rest of the mouse, leaving only the offset surface. Now create an uninterrupted line all the way around that surface, and use that line to extrude in such a way that you are left with a convex impression of the top of your mouse in the extruded block -- an impression that is slightly smaller than the actual mouse. That's what I'm trying to accomplish.