Thanks. Haven’t tried removing the backdrop/ground-plane no… 
I’ll try that too… I do compositing, but haven’t done any on these images… I’ll try that to at some point… I need to add some more details to the model, like interior, and also blinkers on the side, and some audi-logos… I have also noticed that the rails on the roof are missing… I also had a sun-roof on mine… Maybe i’ll add that too…
Looking good! The glass looks better too.
Here’s a new little update… Tried with the HDRI background, and a shadow-catcher plane… I can see that the HDRI is low-res, because of the blur close to the camera… Else i have a tiny amount of DOF to try to remedy that… you’ll just have to forgive me for that… 
Okay, hack away… 
This could be good. It looks rather dark now though with the current car color, and my only other critique for now, is that the rims seem a bit flat in lighting and modelling.
I’ll have to look into the shading on the rims… They are modeled pretty closely to the originals i have in my garage… I tried with another HDRI, just to see if it looked more natural… struggeling a bit with distortions in the HDRI though… well, here the other version…
-c-
I’ve played a little with pbr-shaders, and also god sibl working in blender… C&C please…
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Nice modelling the car feel solid, not sure about the hdri, it doesnt feel in the same place has the car, i like the lighting of the green car in the parking.
Wow, this looks really good!
Alex_L: Yeah, the lighting in the car in the parking is as close to real as it gets, as it is a part of the sIBL image… 
Only the audi is 3d though… But i can see mistake i did myself now, the shadow from the car is lacking, as you pointed out with the other car, it’s lighting looks better, and one of the reasons is the sun-cast shadow, which makes my lighting look off… I’ll try to look into that…
Erhm… correction… I thought you were talking about the car in the pictures from the desert… Not the other one further up… There is a number of strange stuff going on with that… but the car, kinda looks okay there… Maybe i’ll try another sIBL image for size laterz… slight misunderstanding there… hehe.
bonrw1: Thank you very much, i appreciate that compliment very much.
Okay, I did an update… I had to change the shadowcatcher material that was default from sIBL. It creates a AO shadowcatcher, but that kinda excludes the nice sun-shadow… So i changed the shader from ao to diffuse, and did some color-correcting on the plane to make it match the background image. Looks a lot nicer… Also dialed down the saturation.
Just to try the parking-lot hdr again, with proper sIBL-setup. Personally i like it better than the previous version.
Did some small updates on the car. New rails on the roof, side-blinkers, and removed the hood-ventilation thingy… It looked too cheesy. Did some modifications on the roof, cause it seemed to high from the windows and up top. So now the roof appears slimmer… Also did some more compositing to make the car blend in better…
Edit: Dark area on the car was way too dark… couldn’t see the details in the grill…
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All good improvements! Maybe try lighting the front of the car a bit more? (more even lighting in the scene). As you can see from the trailers in the background, even though they are facing away from the sun, they are still lit.
I tried lighting the front a bit more, however it gets too light, and after checking out different reference images, i saw that the original dark-green color, actually comes very close to black in shadowy areas… Depends on environment of course, but i think the main problem with my take on this is the fact that the background seems a tad washed out, hence the shadows of the car and the dark areas seem very dark in comparison to the dark areas of the background… I have one problem though… And that is the fact that there is no shadowcast only shader yet… If that was the case, it would be possible to make the shadows under the car more subtle, and also much easier to control… Cause when i try to create more contrast in the background, it ends up making the shadows under the car even more harsh… 
Well… i’ll see if i can figure something out…
-c-
Today just wanted to try something entirely different, so i smacked in the values for rsblue, and put it in a studio instead of HDRI background… Seems it works a lot better than the HDRI for the moment…
Also did a green version just to test the different colors.
So, that’t my fun for today… And as a side-effect. The dark areas of the green doesn’t seem too dark here…
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Try to turn off the film emulation，may be you will get a better result