1. at first you need to "Merge" your objects into one mesh.
2. with it selected go in UV-Layout
3. call UV-Mapper and set "Mapping type: Frontal"
4. check the tiny representation of the mesh in UVs window
5. while in camera mode have a good play with view angle and Field Of View (alt+/shift+alt+scrollwheel in 3d view - checking UVs
6. you can Write UV coords now and then to check out UVs more clearly.
7. Once you´re satisfied with the angle "Write UV coords" a last time.
8. To get rid of hidden lines/edges you can use Paint select with the Selection tool and "Visible" checked to select only polygons facing you´re/camera view.
9. Invert selection and delete.
10. In UVs window Save UV´s to PDF (make 1 UNDO to get back deleted polygons of your mesh before saving the file)
11. Open in Affinity Designer or other SVG editor and adjust color fill, line thickness, Z-order etc.:
I've been working out carpentry dimensions in Cheetah3D for my Dad for a couple of years now and never found a way to get ortho drawings from 3D into Affinity Designer where I could label the dimensions. This is a wonderful solution at the perfect time!
Glad you find this useful.
This is what I usually do: #2
->export to Collada - load into SketchUp and insert my dimensions over there with its Ruler-tool - which works super nicely when you take 1 unit in Cheetah3d as 1m: