Fundamentals II CD - Exercise-2 - Subtract Solids Error Message

[rdrines]

After trying for many, many hours to get through Exercise 2, I've come to the conclusion that something is missing in how the lesson is described in the Video and PDF file, or the drawing has an error in its line source for the top of the corkscrew.

Problem Description:

Working through the NURBS tutorial in Lesson 2 seems straight forward and everything goes fine, until the user is ask to Subtract Solids for the "Corkscrew Top". That part of the lesson begins on Page 6 and continues to the top of Page 7. At that point, the user is asked to align the objects and then to engage the Subtract Solids command.

When that action is taken, VW displays this Subtract Solids Error Message.

For what it is worth, I've studied and tried this lesson so many times that I was certain I was missing the obvious. At that point I decided to create two other solids, a flat plate and a cylinder. Following the instructions in the PDF, the X, Y & Z centers were aligned and then the Subtract Solids command was executed. Everything worked fine with those two components. Then I tried the Cylinder and the base of the Corkscrew, and again all went fine when the cylinder was subtracted from the base.

At that point I reversed the Solid Subtraction and then tried to remove the Cylinder from the Top of the Corkscrew, but this time the same error message appeared. Something in how the top of the Corkscrew is created is stopping the Solid Subtraction.

It seems as though the program isn't believing that the base (or the test cylinder component) can remove the area where the base and the top overlap. More than likely an calculation error is the source because if an added instruction is inserted into the lesson telling the user to move the top further into the solid base, then the Subtract Solid command will remove the material leaving a smaller version of the top available for the next step in the corkscrew handle construction. Why moving it lower solves the problem isn't clear because the base already encompasses the entire lower portion of the extruded top. All that is accomplished when the top is moved lower is to increase the margin between the walls of the base and the extruded top.

Here is a VW file example (Subtract-Solids-Problem.zip ) that can demonstrate the above problem. Included are the instructions on how to demonstrate the problem.

Any ideas on what may be going wrong?

Any help will be appreciated.

[mike m oz]

Roger - I have tried on my setup and get exactly the same outcome as you.

[rdrines]

This one has been a head scratcher. Clearly the process in the Video is working, but when it gets to making it happen in VW 11.51, I run aground. Maybe this is a version change problem. Hopefully, others with earlier versions will try the process and report their results.

Thank you Mike. I appreciate the effort and feedback.

[Peter Huggins]

Hi Roger,

This problem is caused by a bug in VW 11.5. When the exercise was created (for version 11.0) it worked exactly as published. Here are the steps to complete the exercise, starting with Page 5, Step 3:

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Choose the corkscrew top layer to make it active. Choose Revolve with Rail and click once on each of the three surfaces as show. Do not Shell the object at this time.

Select the object and the extrude and choose Align/Distribute 3D. Align and Center the objects along their X and Y axes.

With both objects still selected, choose Subtract Solids from the Model menu, and highlight the surface as the shape to be retained.

Now select the remaining object and choose the Shell Solid Tool. Open the tool's Preferences box and enter a Thickness of .1". Highlight the object and press the Enter key.

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Basically, you are simply changing the order of operations and using the Shell Solid Tool at the end instead of the beginning.

Hope that clears things up and sorry for the confusion.

[rdrines]

Hello Peter,

Your solution worked on the first try. Thanks for jumping in with the information.

In your message you mention it is a problem in 11.5. Has that been communicated to VW_Engineering, or should I send them a note?