I have been using SolidWorks for a number of years. I found that SketchUp is very easy to create any object. However, I found that it is difficult to make changes in some cases.
For example, after a fillet is created, how do I change the radius of the fillet without redrawing it? After a hole pattern is created, how do I change the spacing, number of copies, and hole diameter?
Can someone show me how to make these kinds of changes in SketchUp?
Basically, you don’t - you recreate it. That can be done with the native tools using FollowMe, and redrawing the fillet with a new radius. You would probably also need to change the faces bordering the fillet to the new transition position between face and fillet.
With a few exceptions, SU is not a parametric design program. There are some plugins that use changeable parameters to edit a component after it is drawn, on the fly - for example, one I published as the SU Draw Parametric Shapes on the SketchUcation Plugin Store. There’s a slightly earlier version on the Extension Warehouse which includes fewer shapes.
And Dynamic components to an extent allow you to do the same.
As for changing a hole pattern, again it is usually simpler to recreate it with the Move/Copy command, or Rotate/Copy (that is, the Move or Rotate tool plus the Ctrl key (or Option key on Mac). Both operations are quick, and you can type in the number of copies required, after making one copy - use n x where n is an integer to make n copies at the same distance or angle as the first copy relative to the original and x is the letter x on the keyboard, or n/ to make n copies equally spaced between the original and first copy, and / is the slash key on the keyboard.
I forgot to say, that for changing fillets, you could keep a copy of the original unfilleted component, make a Unique copy of it, and apply Fredo6’s Round Corner plugin (it also needs you to install the LibFredo plugin first).
In many cases, that is quicker than using FollowMe.