Alice:  Troubleshooting and Debugging



Symptom

Hint

Alice won't install First, check whether your machine meets the minimum hardware specifications. You may try running Alice by clicking on the icon labeled "Slow and Steady Alice".
If your machine meets the minimum specifications, there might be a problem with a file Alice creates called .alice. Depending on your machine configuration, this file might be located at C:\users\<userid>, or at C:\Documents and Settings\<userid>. Remove this file, and restart Alice.
If this doesn't work, we have found that if the path contains non-English chracters and/or if the input language is set to something that contains double-byte characters (such as Chinese), Alice will still not start, and one or both of these might need to be accordingly changed.
If after making these changes you still cannot start Alice, send email to the Alice team. Include your Operating System, processor, and graphics card information.

Your Alice world doesn't load. The most likely reason a world does not load is that the most recent "Save" ran out of space. For example, a world that occupies 3 MB of space will run out of space on a 1.2 MB floppy disk. We recommend that worlds be saved on the hard drive, a zip disk, or a memory key where running out of space is unlikely.

If space shortage is not the problem, then file a bug report at the Alice Bug Database.

Null pointer error 1) Look for an instruction where "none" was specified instead of an object. Replace "none" with the name of an object.

2) Look for a method call where a parameter was not specified. Provide an argument for the parameter.

3) Did you cut and paste code from one method to another where the methods each have a parameter of the same name? If so, in the method where the code was pasted, drag and drop the variable tile onto every instruction where the variable occurs.

A function is not returning the correct value. Use the print instruction to print out the value being returned by a call to the function. This will likely help you discover what is wrong with the function.
We have found that you can change the color of some objects but not all. For example we can’t change the horse’s or bunny’s color. The culprit here is “shadingStyle” a property that can be found under “Seldom Used Properties”. In the problematic objects, it is set to “none,” rather than “smooth.” Unfortunately, changing this property probably won’t give you the results you want, either. This is simply a flaw in several of the gallery objects, and the Alice development team apologizes for the inconvenience.
Adding 3D objects using the mouse to drag and drop them into the world does not work. If you have removed the ground from the world, the drag and drop cannot drop the object onto the correct location of the world. We recommend removing the ground last, after all of your 3D objects have been added.
The .WAV file that I have imported does not play.

Can Alice play the default .WAV files (these show up in the drop-down list when you issue a playSound instruction)? If Alice will play the default .WAV files, the file you imported is probably not a real .WAV file (even if the extension is correct).

If Alice will not play the default .WAV files, then either contact us or file a bug report at the Alice Bug Database.


Contact Information:

     Wanda Dann: wpdann@andrew.cmu.edu
     Stephen Cooper: coopers@stanford.edu
     Don Slater: dslater@cmu.edu