There are some very frustrating problems with SketchUp.  In general, the "Pro" features (which require paying a substantial amount of money for a software license) are much '''less''' polished than the free features.

'''Bugs due to hidden variables'''
* Components have a set of hidden variables that control the scaling.  Unfortunately, the UserInterface does not provide any way to see what these variable values are, let alone set them.

* It is not safe to incorporate a dynamic component into a parent component, unless all of the attributes of the child are "fixed" by placing an equals sign in front of the component.

* The UI has no setting to "fix" all of the attributes of a component, so that it is safe to incorporate into a parent component.

'''Problems re-using components'''
* Google consistently uses the same word "Component" to describe both a Class of components and an Instance of a component.  This leads to some corollary problems.  For example, the UI makes it very difficult to tell whether one is editing a property of a single instance, or of an entire class.

* There is no "Parent" pronoun that can be used to generically make a component depend on a property of its parent.  This means that once a component is made to depend on one parent, it needs to be recoded before it can be made part of a different component.

* There is no default behavior for "orphaning" a component.  That is, taking a component that gets information from its parent, and letting it have default information if its parent is missing.


'''GUI Lag'''
* Auto-saves take place in the foreground, instead of in the background.

* The UI experiences severe lag whenever an auto-save occurs.

* In the 3-D view panel, middle-clicking (to use the orbit and pan tools) often does not work.

'''Other Problems with the Component Attributes Dialog'''
* There is no hierarchical namespace for components, so component names become very long.

* The UI's Component Attributes dialog's titlebar for each component only shows the first few characters of each component name.

* The Component Attributes dialog box does not list two standard properties that are needed by many components.  (The full list of standard properties is at http://sketchup.google.com/support/bin/answer.py?hl=en&answer=114551) These two standard properties are missing from the UI:
** Creator
** Copy

* The UI does not provide a way to export the attributes of a component to a human-readable text file.

* The Component Attributes dialog does not allow viewing the formulas and the current values side-by-side.

'''Other UserInterface Problems'''
* The UI's use of the space bar, enter key, and escape key is not consistent with similar programs (such as AutoCad).  Worse, it is not consistent from one part of the UI to another.

* The UI does not remember the state of the dialog boxes from one session to the next.  For example:
** Even if you used the Component Attributes dialog last time, it does not appear at the start of the next session.
** Even if you re-size a dialog box (to fit between the 3-D view panel and the edge of the screen, for example) every time you use the dialog box, the dialog box always starts at the default size.

* Many error messages produce "OK" box pop-ups, but do not include any link to an explanation of what is wrong, let alone how to fix it.

* The "Offset limited to" tool-tip is not intelligently placed.  It normally appears slightly to the right of the mouse (with a slight lag).  This makes it very easy to click the mouse on the tool-tip, resulting in the mouse-click being ignored.