Heya what program does everyone use to build custom scenery and structure's? I want to make the 3D isometric objects from scratch without coding if possible! 

Sorry if this has been asked before I did search the forums already

Cheers!

Unfortunately I can't answer that question. I only use custom scenery

I know a lot of the people who were making CS were using software called SketchUp. I actually had an old copy on my old desktop. I made a few walls but nothing super awesome worth mentioning, I never got-good-at-it or anything. You could probably find an old copy of it floating around and there are still tutorials on youtube. Hope this helps.

I wonder if you could use a CAD program.  If you are able to save it in the right format, that might work.  I'll have to give it a try
I have TurboCad and I'll let you know if it works.

I tried using TurboCad but it just wouldn't save in the format that we need for RCT. Sorry guys, I tried.

Just to lay this thread to rest, SketchUp is compatible with NoLimits, not the RCT games. Autodesk products (such as Revit and any CAD program) are also not compatible with RCT. There were programs around for making RCT CS back in the day, however they are not on site as far as I know.

If you want to try making CS for RCT2 check out NE Designs as they have an active community that does that:
https://www.nedesigns.com/

If you want to try making CS for RCT3 check ShyGuy's World/CSDepot as that's the only active RCT3 forum out there that I know of.
http://www.customscenerydepot.com/index....wwRedirect
http://www.shyguysworld.com/index.php?PH...wwRedirect

I used Sketchup to make a set of dripping walls about 5 years ago for rct3, it's a pretty complicated process and I lost interest after about the 3rd wall set but I can assure you my copy of sketchup worked for rct3. Here's a tutorial by Silvaret:

and 2 more
https://www.youtube.com/watch?v=3GX475SS720

https://www.youtube.com/watch?v=UqlemKIreR4

FYI Sketchup 2017 has NO Plugins for RCT any version or any other game or instance.