Its important to create all mutli-angle views at the same time...maintaining the scale.
I use the side view to extrapolate the angular points outwards to the front and rear views.
Top view can be extrapolated in the same way as you see in the image.
This is also where I will check overall width/height/length dimensions to see if they are to proper scale.
I refer to actual manufacturers dimensions, but those are often dictated by extra parts that stick out from the main body,
different size wheels and tires, and other factors.
Since my model will also have angular features and stylized areas, I only take the real dimensions as a "rough" reference.
Another factor to consider is a peculiar visual effect of small scale car models.
I often widen the car beyond its scale dimension (related to the length).
Models can appear too narrow at this small scale (if everything is to proper scale, width vs length).
Many car models look visually better if they are stretched wider, so I will often add 2-3mm width to compensate.
Creating the multi angle views is important for determining proper angular dimensions...
from one angle a part looks one way, but from another angle the actual measurement of that part can be determined.
For example, the side view shows me how tall the roof is from the ground (or from the shoulder of the car)...
but the front and rear views illustrate the actual length of the side part (up to the roof) because of the angle as the roof narrows.
So when I start laying the actual parts from my drawings, I can stretch out parts to the proper dimensions, so that when assembled, they look correct.
*The side part in the drawing below is the actual foldable paper part with its adjusted height dimensions.
Once a part is established, it can then be used to extrapolate the perimeter dimensions, and the dimensions of all the parts that will connect to it.
I can create the center roof/body part (made up of several folding sections) from the multi-angle view...
but the actual length of each section will be derived from the adjusted side paper part.
I take a physical length measurement of each body edge and then transfer it to the related section of the center part.
I will go back and forth between connecting parts making sure that these measurements match.
