I rarely use it for rooms since they're all based on 90 degree angles, and I feel fairly confident about those. But, when it comes to vehicles, especially if there's a certain make or model that you're after, 3D is super great because there's a lot of car people making car models that are fairly exact so you just have to download em, drop em into blender and go. My process is first, a sketch. (this is only part of a page)
As you can see this is a very well designed Tesla. Very detailed.
Then I found a free model instantly that had no restrictions on copyright via one google search.
After getting it in a position I liked, I didn't even bother rendering, I just did a print screen and cut it to fit my comic. (I also went in with the warp tool to sort of exaggerate it a little bit) My current comic is so stylistic that I'll have to redraw it to match everything else.
reduce the opacity and lock the car layer
and draw, making sure to not just trace, but also still pay attention to form, flow, and all that. You still want your line quality to feel organic although it's a 3D render.
And then some pops because this is an impact panel about how excited Fred is to drive this car.
and that's it. I can move on to drawing about (looks at notes) way too many other positions of this Tesla in almost every other page before I will absolutely crash this car.