I'm a new user of SketchUp and have been very impressed with the program and how easy it is to learn and use. I've run into an issue that I'm not able to solve. It may be that the program will not do what I'm wanting to do....... anyway, If anyone can tell me how to accomplish the following I'd be very appreciative.

I have created a rectangle, then pulled it up to create a block. I have constructed an arch for a doorway and I'm able to pull or push that arch all the way to the other end creating a vaulted void in the block. All of that is quite easy and works well. However, now I want to slice that block at an angle, keeping the vaulted void through the block. I'm not sure how to accomplish this.

I'm using the free version of SketchUp and wonder if I just can't do what I want unless I purchase the Pro version.

Thanks for your help,
John