I've just purchased the professional version, so I'm not sure if there is a suggestion area or not, so I'm posting this here.

 

I'm happy with the professional version, especially the primitives since I prefer to scratch build structures, but there are a few things 3D-Train Studio could use.  One is a curved primitive.  The uses are almost limitless, such as archways for scratch built buildings, but it would be great for making curved train bridges and trestles. 

Since curved rail can already have their angle and radius adjusted, would it be much harder to create a primitive with these capabilities, and the ability to set the height and width?

Also, how about a little more variety in the diesel locomotive section such as the EMD GP-class and SD-class Diesel Locomotives, and the EMD F and E Cabs?  These are probably the most popular cabs in the United States, and they would definitely be appreciated by your American audience.  I was even hesitant to buy the professional version because of the limited variety of diesels, so I imagine there have been other prospective American buyers who didn't purchase the professional package for this reason.

Also, your rolling stock is very dated.  You could use some modern boxcars, hoppers, and other equipment.

Hi Badattitude

welcome!

Model-wishes take a while, but it`s give action to improve matters.

It`s easy, to built the diesel locomotives himself. I show you with a picture, because to be missing the words to me. Sorry for my bad english!

in this regards: Modellbahnspass

Thanks Modellbahnspass.  I'm actually in the process of scratchbuilding some engines.  Since the EMD GP-class and SD-class Diesel Locomotives are longer than the Tegernsee-Lok, and the body is more narrow than the rest of the diesels, I'll be using the Schwerlastwagen kurz, Schwerlastwagen, or Container Wagon lang for the trucks, and an invisible Sattelzug-Zugmaschine-Fahrgestell as the drive unit.  

I hadn't thought about using the Diesellok (rot) for EMD F and E Cabs.  Thanks for the idea, I'll give it a try.