Unable to erase A Shape Without Erasing An Object Its Attached To?

I have a window, and below it I am trying to create a window sill. I created a rectangle and moved it into place under the window. But I don’t like it, but when I try to erase the new rectangle it erases the window also.

What must I do to ensure I only erase the rectangle sill?

(wanted to put in a before and after pic but I guess I’m too new)

Share the SKP file so we can see exactly what you’ve got going on.

By the way, it is best to hold off applying materials until after you’ve completed the geometry.

Offhand I’d say you need to learn how to use groups and components correctly. They isolate bits of geometry so they don’t interact with stuff in another group or component.

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Hi Dave, apparently my skp file is toolarge to attach.
slbaumgartner … I’m certain I have more than just that to learn!! :slight_smile:
Only when I started learning from my mistakes that I’ve discovered just how powerful this software is when you learn what its capable of!

First try purging your model of unused stuff. Go to Window>Model Info>Statistics and hit Purge Unused. Does that reduce the file to under 3 Mb? If not, upload it to Drop Box and share the link.

My Model

Steve was right. You need to learn about using groups and components. Your entire house is loose geometry which makes it difficult to work with.

When you erase the bottom edge of the window sill, SketchUp is healing the face. If you’d make a hole in the wall for the window and use a component for the window, this wouldn’t be a problem.

It appears the edge at the top of the sill isn’t quite on the surface. It’s close but not close enough.

OK. Definately learning things from my mistakes. Working now on understanding groups (straight forward) but components requires a bit more digestion.

I think there is an approach to creating models that needs to be learned as well. For instance, cutting a hole in the wall and inserting the window, where as I think I’ve just been adding things to exisiting faces. My approach might need improvement to.

Thnak you!!

It would be worth your while to watch the intro videos at

Components shouldn’t be that much more to understand than groups.

The thing you need to get down is that geometry is sticky so your house is sort of built like it’s made of wet clay. If you make the walls and group them, then add the windows and doors and other details as components, you can more easily work with the model. Make the roof as a separate group so you can easily remove it to work on the inside. Things like that.

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Further to @DaveR comments, when I first started using SU my frame of reference was i am “drawing electronically”. As I learned and adapted to the power and structure of the program my reference frame became “building electronically”. I think of each element in my models as a physical element be it a wood stud a window or a roof, each one discrete, manageable and reproducible. Wishing @MaxArk68 good luck and patience with your learning curve.