Here you can find:
Select PlaneShift->Export Level.
This is the export dialog:
Export Level To: In the first field you should specify the export filename including its full path. Ex.: d:\myStuff\CS\levels\level1\world.txt
Scale: This indicates which is the scale to apply to the current scene while exporting, if you follow the guideline of "1 meter = 1 generic unit" you can place "1" in this field.
Export!: This button starts the export.
Copy textures to dest dir: If you check this option, a new dir will be created in the same dir of the output file and will be called <filename>textures. In this directory there will be copied all the textures files present in the scene (the ones used by objects). Multimaterials are supported.
Generate Fake lights for walktest: If you check this option, the exporter will add to the world file generated also some animations used to test the day/night setting of all lights present in the level. If you check this option you must add a value in the next field.
Duration (msecs): tells the exporter how much time each hour (1 frame=1 hour in max) will last in the fake light simulation.
Rename the generated file as "world" and copy it and the textures in the directory you just created.
Open a console , cd to your directory (typing cd /the/path/to/CS ) and run "walktest /this/data/my_scene_name -relight"
If you want to fly while visiting the level in walktest you can just press '8'. This will disable gravity.
If you want don't want to recalc all lights because it takes too much enable
bugplug and then press CRTL-D followed by L while in 3d view. To enable bugplug
you simply have to edit the walktest.cfg file located in data/config (or bin/data/config).
In that file locate this line and remove the starting ';' char.
System.Plugins.iBugPlug = crystalspace.utilities.bugplug
Bugplug will also enable the FPS display in the lower left corner of the 3d view.