Ahh…reading this thread reminds me of all the things I learned by trial and error over the years. I’d like to add my two cents.
I always make my cutting plane into a group. If I don’t, and any edges touch edges of the geometry to be cut, I will have problems due to the sticky behavior of ungrouped SU objects. If the cutting plane is a group, it can’t stick to any other geometry. The other benefit is that once the intersection is done, I can just select and delete the plane, instead of having to make sure I got all its parts, as I see in some of the illustrations.
Another benefit is that in a complex model where I have numerous components or groups comprising an assembly (i.e., a roof eave with fascia, trim, underlayment, shingles, etc.), I can instead of deleting the cutting plane, cut it (i.e., CTRL-X) instead. Then I back out of the group I’m in, go into the next group in the assembly I want to cut, and paste the plane in place, repeating the intersection process, and doing that for all parts of the assembly. (Hint: make a keyboard shortcut for paste in place. I use CTRL-ALT-V).
Finally, wherever possible, I always use intersect with SELECTION instead of with MODEL. It’s too easy to accidentally intersect with hidden geometry that you can’t see, only to find you have hours of cleanup to do later. Intersect with selection assures that you’re only intersecting with things you can see.
I can assure you the hardest thing about making my examples is to do them using the most rudimentary methods.
They are to explain the basic, not more advanced methods.
Usually I also have the toolbar in view and select the tools without using any shortcuts.
Thanks again for all help. I appreciate the comment that the plane should be made into a group. I just made the cut again, and with that suggestion, all went well. I did have to use “intersect with model” as when I used “intersect with selection”, it said there were no intersections.
By the way, as you can tell, I am still a novice with sketchup, but can you tell me the effective difference between a component and a group. If it would be better for me to start a new subject regarding this, just let me know.
A group is basically an individual whereas a component is one of many.
If you have several copies of a group and you edit one, it only edits the one you edit.
If you have several instances of a component, edit one and they all edit.
A simple example, build a picket fence with components, drill a hole in one and they all get a hole.
Build it with groups and you spend your life drilling.
Components have other properties also, like glueing and cutting etc
Besides the spot-on info from Box, the other great value of components is to reduce your file size. Each “group” in the model adds to the file size. For simplicty’s sake, whatever one particular group would add, 10 copies of that group would add 10 times as much to the file size. When you make something into a component, each additional instance doesn’t add the additional overhead of the all the geometry, just data about its location, orientation, etc.
This is something you will have to learn in time to plan from the outset of a model. There’s no downside to making your first instance of something into a component rather than a group, if there’s any possibility you’ll want more than one of them. If you have already made 10 identical groups and realize you should have made it a component in the first place, there’s no way to make those into 10 identical components without replacing each one individually with your new component (unless of course someone’s made a script for that).
But if you started out by making it a component, you can save it for re-use in another file (see context menu), and once saved, it can be reloaded to replace another component. And if you decide you want 5 out of the 10 to be different from the other 5, you can select those 5, click “make unique”, and you can now modify one of those to affect all 5. The component is your best friend!
Select them, convert them to components (there is a plugin for that) then use the component browser to Replace Selected. You can replace hundreds in one click.