Bug? Trying to put a hole in a revolved surface.

Experienced CAD user, new CorelCAD user.

I'm trying to draw a pulley.

I start with two parallel lines, with an arc connecting the top of the lines.  I then use

  Solids-Draw-Revolve

with the axis of revolution being the bottom of the lines.  Ta-da, something that looks like a pulley.  I can twist and rotate (Rollview) and it looks exactly like what I expect.

Now I want to put a hole in middle of the pulley (because pulleys run on shafts).

  Circle - Extrude.

  Solids - Solid Editing - Subtract.

Doesn't work.  When I try to specify the entity to subtract FROM, CorelCAD never finds anything.

I think I know what I'm doing, as I can put a hole in a cube.

  Rectangle - Extrude.  

  Circle - Extrude.  

  Solids - Solid Editing - Subtract.  

works fine.

But there's something about the "solid" made by revolving ...

Any thoughts appreciated.

Parents Reply
  • 1513.Alclad Base Plate with 3rd Flange 07042015.dwgThanks cj7hawk,

    They are very useful steps to remember. However, I have had no luck with those steps even though everything looks to be aligned and touching.

    I have attached the modified base plate and flange file.

    There were two approaches I took initially.

    The first was to draw the 3rd flange with lines, changing the lines to polylines, creating surfaces but I couldn't make a solid out of that despite all points placed with respect to the specified CCS origin . (Not sure why one cannot do that, as that is intuitive.)

    So then I made the end concentric arcs, closed the arcs with lines, created a polyline around the arcs and ends. I then extruded this 4.44 inches along its on Z axis. I don't actually like this because if the ccs is slightly misaligned to the edge of the place, you will get a misaligned extruded edge/face.

    Anyway, I then used Separate from the Solids > Edit Solid menu. When this is invoked it asks you to select the entities then asks again the action i.e. seParate I found that a bit weird.

    I checked the entities were separated and went to Modify, 3D Operations, ALIGN3D. Then it asks for the base point, second point and, third point. Then it asks for the destination points which you lay down in the same order according to Help (for ALIGN3D).  

    I specified my points with exact coordinates x,y,z. Whilst this alignment is taking place the flange flips vertically before finally aligning itself adjacent to the base plate top edge 0.040 wide surface as the 3rd and final destination point is entered. Under great magnification, all looks good.

    I then Unioned the entities.  I checked I had a single 3D solid in the properties box after that. But if union can Union without things touching what is the point of Union?

    *************

    At this stage I wanted to test if I could put another hole in

    (1) the main part of the flanged plate

    (2) just the 3rd flange

    (3) through the 90 degree corner of the 3rd flange and the existing flange of the plate

    None of these holes could be created.

    (The method I used to create the holes was to set the CCS to the sharp corner of the third flange and existing flange with x axis along the plate edge, y along the face of the end of the third flange, and z axis parallel to the straight line edges of the concentric arcs.  The origin of the ccs was put adjacent the top face of the plate.  So it SE Isometric, the ccs is siting in the tope left corner of the plate on its face.  I then specified a diameter of 0.08 inches, with z = +/- 0.5 and extruded that through the plate, using the Subtract function to create the hole. )

    The plate was originally extruded toward the 3rd flange and I had wondered whether the extrusion of the 3rd flange orthogonally with a reoriented ccs may have created this problem.

    Just FYI the cad engine in Autodesk's AutoCAD 2015  is doing the same thing.

    What is happening with this plate to cause this problem?

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