I think there is a problem with the terrain settings in the world settings panel.
Note make a copy of "The big escape.fpm" file. Rename the copy created. Use the copy for the following...

Example:
Open the (the name you used for the copy.fpm". file. In the test mode press the TAB, TAB and display the panels. Make note of the terrain type displayed in the world settings. In the world settings panel under terrain type change the the terrain to a different terrain. Make note of the new terrain name. Save the copy file that now displays the new terrain. IMPORTANT Exit GG. Open GG and open the file you just revised. Run test. The terrain in the just revised file will not show the terrain that was just changed but it will show the original terrain not the new one. TAB, TAB to display the World settings panel which will display the name of the revised Terrain as it should.But that new terrain will not be what is shown as the terrain displayed in the map. If you look at the DAT file in the mapbank folder you will see the dat file contains the Terrain type name in the copy file you have used but will never display the terrain file you want.

This problem does not appear using smaller maps but does when, terrain changes are made, in maps of similar size to The big escape.
If you verify this is a bug let me know and I will try to post this to "GitHub"
REMEMBER do not use the original "The big escape" file you must use a copy so as not to corrupt the original.

It's probably because the map is lightmapped. If you lightmap it again with the new terrain it should show the new terrain.

The big escape may be lightmapped but my own large maps are never lightmapped and they display the same problems. When I get back from a meeting I will try to lightmap the big escape after I change the terrain and see if it makes the problem go away. Will get back to you...

The big escape is not lightmapped. I don't think that is the problem.
This is what I get when I load The big escape into the editor before or any time after changing terrain...


This is after test, tab ,tab ,here after I change terrain to cartoon terrain, save and return to the editor.


This is what I get after returning to the editor after change but before the exit.




This is what I get any time before or after any exit and reload of the revised map terrain setting.


Note: after I change the terrain to cartoon and check the DAT file in MAPBANK the terrain is shown to be set to cartoon, yet when I run the "The big escape" it displays the map type as "cartoon" in world settings but displays the original terrain type from the big escape when run in test mode.
Refer to the screen shot for a larger view of the revised terrain setting showing that the terrain has been recorded but the terrain being used is NOT the cartoon terrain.

@m2design, firm hand shakes on the detailed post. can confirm I am also seeing the same results following your break down. At first was considering an increase in texture data added to the .fpm something I have covered before, though seems something else is happening. Personally I don't suggest any texture change, terrain or builder carried out during a level build.

@Defy
Thanks for the confirmation. I was afraid it might be a problem with my system. Based on our results I have reported the problem on GitHub.
The interesting thing is smaller size maps don't seem to be effected... but all of my larger maps are.
My first thoughts were the problem was due to all of my custom entities, not so...
Again thanks for the time spent.

Looks like a bug when saving a terrain that formerly had a custom texture that then has been changed to a standard one. The engine is still saving the custom textures into the FPM even though not needed as a standard 'texturebank' terrain has been selected and indexed. Can't see any issue with large maps over small (yet).

Thanks for the detailed step by step to illustrate the issue m2design.

cpp code fix that works for Cogwheel (for the engine):



Cheers.

@cybernescence
Thanks for checking this out. I hope Lee will fix the problem sometime … I added it to GitHub as a bug but have heard nothing.

Not knowing any thing about adding code to the engine (what is cpp) I will have to wait. Again thanks for the information.

Preben sent an email stating this issue has been resolved, ready for the next update.