https://www.thegnomonworkshop.com/tutorials/creating-a-custom-3d-kit-for-concept-art

all the insights and techniques to help you take full advantage of 3D kit creation and be inspired to produce epic images, from generating initial ideas, gathering references, and handling prep work to finalizing concept art in Photoshop. Everything will be covered to help you create your own 3D kit assets, including modeling and texturing assets, from single assets to more complex pieces, assembling new assets, and building out a scene. You’ll then explore how to use the created assets to build final illustrations.  The workflow instructed offers a comprehensive approach to asset creation and scene development, beginning with hand painting, bashing plants, and using Blender texture nodes to generate individual assets. Those assets are then developed into a versatile kit, employing Blender techniques, including mirroring and deformers, to progress from simpler to more intricate components.  Upon establishing a substantial asset library, the focus shifts to conceptualizing building assets. This involves leveraging straightforward Photoshop painting techniques to refine the final concept. The subsequent phase involves constructing a complete scene using the compiled kit. Additional techniques include simple modeling and sculpting in ZBrush as well as the use of VR with Gravity Sketch, transitioning to assembling the scene in Blender with the developed kit.