Sphere and Contact Challenge example file error

[sitangshugk95]

I am trying to run the Sphere and Contact Challenge example files.

Both of them throw out the same error:

Was this code tested when it was merged? I am guessing just changing the way I am inputting the file should not cause an error, but I might be wrong.

[sitangshugk95]

@sannant I was not able to test these when you wrote them as I was moved to another project. I am resuming this now and trying to go through the example files that you wrote. Do you have any inputs on this?

[sitangshugk95]

The issue with these is that the substrate was not defined - I have fixed them locally and will merge the corrected versions soon.