A couple of questions:
Do you have a model seat that has been UV unwrapped to bring into Photoshop or Dimension ?
Neither Photoshop, Illustrator or Dimension is great for creating a model from scratch. If you want to create from scratch then you would be better using a full 3D application e.g. Blender.
If you do have a model, will you be creating textures or using pre-made textures?
Dimension uses physically based rendering, which is more realistic and is expecting texture maps to meet its shading requirements i.e. Base Color, Metallic, Roughness, Normal
Blender can be set up to use physically based rendering (PBR) Metallic workflow as used by Dimension but also has the shaders to deal with most other formats.
Photoshop looks for a different set of maps - Diffuse, Specular, Shine, Reflection, Roughness, Normal . Sometimes you will nee dto adapt the maps to get the surface to work if not all are available.
If you are intending creating your own materials from scratch then Photoshop or Dimension will do this.
For an introduction to Photoshop's 3D capabilities see these tutorials. They use CS6 but little has changed in Photoshop 3D since CS6: