Level Maker 3D has been sitting on my hard drive for a couple of years now. I have no time at all to update it, and if I did I doubt I would do anything else to it.
So, I have archived the complete LM3D source code, along with the images, loader code and action system under the GNU licence. If you want to see Level Maker 3D in action then please download the Krazy Karts source code from
http://www.levelmaker3d.co.uk/krazykarts/
The code was written for DBC v1.3 Enhanced, you can easily make it for DBC v1.3 unenhanced by hardcoding the ini file reading.
I have once tried to get it working in DBP, and it did work ok, but alas I cannot find the code on my pc/backups. There are some variables in there which start with numbers and so they need changing. Overall, the code is not very complex, it just handles all the boring mouse clicking for the GUI and other things. So, I give it a Beginner -> Intermediate rating.
Thanks for looking, and I hope it is of use to you!
http://www.Levelmaker3d.co.uk