For step-to-step guide on exporting obj properly so it works with OOTP, please refer to Silvam's tutorial here:
https://forums.ootpdevelopments.com/...d.php?t=289916
Since you already know how to build a 3D model, you can just skip to the last step:
Part 4 includes:
View Here
- Exporting the model from sketchup to an .obj (download sketchup plugin objexporter here) Install plugin here:
C:\Program Files (x86)\SketchUp\SketchUp 2016\ShippedExtensions
- Importing and testing the stadium in OOTP19 (fixing anything wrong)
- Configuring the 3D crowd and testing in OOTP19
- Creating the 2D diagram
- Creating the 2D Day and Night Photos
- Setting The 3D Grid and wall markers
- Setting 2D Ball locations
- Creating park factors
- exporting park .prk file