When building a transformation configuration, all build messages will be printed in the UML Development console. This includes both messages from the model compiler (transformation messages), as well as compiler and linker messages produced when building the generated code by invoking make. However, there are also other consoles which are populated by messages during a build. For example, the Model Compiler console contains more detailed messages produced by the model compiler.
To avoid that other consoles pop up when you want to read messages in the UML Development console while a build is running, you can pin the UML Development console by pressing the Pin Console button in the Console view toolbar. Pin the console before starting the build or, in case of the first build where the UML Development console still does not exist, pin the console immediately after starting the build.
By default the UML Development console is limited to a certain maximum buffer size to prevent that a very large number of build messages will occupy too much memory and slow down Eclipse. You can control this maximum size by means of the preference Run/Debug - Console - Console buffer size (characters). You can also completely turn off the limit by unchecking Run/Debug - Console - Limit console output. If you find that, after a build, the UML Development console has been truncated so that the first build messages are missing you can adjust these preference and then run the build again.
Build messages can be very long. To avoid tedious horizontal scrolling in the UML Development console you can use the Word Wrap button in the Console view toolbar. When pressed, long lines will be wrapped so they fit the current width of the Console view.
If you want long lines to be word wrapped when they exceed a certain length you can set a special JVM flag in eclipse.ini:
-Dcom.ibm.xtools.modelcompiler.console.linelimit=500
The value specifies the maximum number of characters in a line. Longer lines will be wrapped at the next white space character.