BMW i8

[Kogomat]

Abstract:
And He said - The only reason I post this, is to get torn apart.

Prefix:
Make no mistake, this project was finished, done, I intend to put it in my portfolio (please stop me if you think it’s not good enough), until I started writing this. I critique stuff on a regular basis so I noticed a lot. Any and all feedback still requested. I suck at making cars. Tried a few times, this is the first time I actually succeeded. So… yay. After about a month… or two. I call this project finished cause I’m not going to go messing around with the model anymore, though I might add interior at a later point. Then again, by then nobody will know what a steering wheel was.

Result:
(can’t embed images…)

http://pasteall.org/pic/show.php?id=111719

http://pasteall.org/pic/show.php?id=111718

I believe my greatest issue is topology. I was hoping it would not cause problems if I subdivided enough but at 4 levels reflections are still all over the place. There are specific places where topology is a mess because I didn’t know how to solve the problem without introducing poles, tris, or a messy loop cut that would cross half the model and mess up subdivisions. Any help/opinon/comment/warning with these (best practices for solving to quads etc) is appreciated.

I made the chasis by parts, which I later joined together. Some are still separate like glass and doors. Because I wanted to join them into a single mesh (in case I would animate the model later (and let’s be honest, who wouldn’t (want to, at least))), I kept edges/vertices in original positions - you can probably see problems this causes on the windshield, and I am wondering whether there isn’t a better way to do this. Fixing topology for each part seperately introduced gaps into spaces between mesh objects, so I didn’t know what to do.

http://pasteall.org/pic/show.php?id=111715

If you are looking at the rectangular shape between the door and frond wheel, that’s probably for gas; I was going to extrude after I applied the mirror modifier, which I never did.

http://pasteall.org/pic/show.php?id=111716

http://pasteall.org/pic/show.php?id=111717

Materials: I did a simple PBR for the majority of the vehicle - two glossy(more and less rough) mixing with fresnel. For white material I used a diffuse-gloss-fresnel setup because having only two glossy created a mirror effect and I could almost not see the car. Sadly, I think this is what makes the render obviously CG.

http://pasteall.org/pic/index.php?id=111723

I have also just noticed that the tires in the end render are pinnacle of boredom. They are normal-mapped because a single tire had as many faces as the whole model does now, but they didn’t come out that well. They look even worse in the final render than individually!

http://pasteall.org/pic/show.php?id=111724

Anyone have any guides on how to light cars in CG? I can help myself with photography, but there are differences. Google didn’t give me anything, btw.

Okay… I think that’s it. Thanks for reading.

[cgCody]

Hi Kogomat. I believe it is a great model, especially for a first complete car.

A few points if I may. As this is focused critique, there are lots of words ahead. Fair warning.
The first thing I noticed were the panel seams not matching up in some places. I know from experience that when starting out with hard surface stuff, there is a sort of fear about selectively adding supporting geometry. When you have two surfaces that meet, it’s tempting to keep the geometry matching, but don’t be afraid to get messy. Sometimes the appropriate geometry might look wrong until smoothing. See the picture below for an example. I would also say not to worry too much about tris and poles when it comes to hard surface. You can always defer them to a more coplaner part of the mesh.

You asked about lighting cars. I don’t have any tutorials to direct you to, but just copy the masters, as they say. If you’re going for realistic studio lighting, then those masters are studio photographers. Treat your scene like a real studio. Use a curved backdrop. Use bounce cards to reflect light back into the scene. Use a blackbody node on your lights so that you can match the color temperatures that studios often use. Giant area lights above the subject will lend interesting highlights. Do a google search for “car photography studio”, and you’ll likely see something like below.

Car Paint. Yours has a sort of toy plastic feel to it. I would also consider changing the color, or adding some colorful objects to reflect. Otherwise you have white paint, reflecting white lights.
Mixing two glossy BSDFs isn’t going to get you the effect you’re looking for. Car paint has two layers; A clear coat (which is typically very glossy) over top of the actual paint (which is often a little rough due to the small flakes of paint.)

Clear coat is a dielectric, which means mixing glossy and diffuse.
The paint layer can be either a dielectric or metallic. Metallic paints are usually on higher end cars (like a BMW i8)
How can you tell? If a car’s reflection is a strong tint of the paint color, it’s metallic.

[Safetyman]

Very good explanation cgCody. I like your node setup there.

[Kogomat]

EDIT: a lot of edits, a few tries, I’ll just go straight to modelling threads. thanks again for your feedback.

If you know any hard surface resources with a lot of talking (theory and the like) it would be appreciated.

Original:

Thank you for the informative critique, I will work on materials in this respect… meanwhile, I am uncertain what I see with the first two images (or just one). I tried to recreate it but did not quite succeed. It looks like you subdivided it and moved the last edge inwards, but when I try to make additional cuts on a subdiv mesh it adds bumps or straightens a surface if it was curved; why is yours still smooth?

example of bump: http://pasteall.org/pic/index.php?id=111853

[cgCody]

Very good explanation cgCody. I like your node setup there.

Well thank ya kindly, sir.

EDIT: a lot of edits, a few tries, I’ll just go straight to modelling threads. thanks again for your feedback.

If you know any hard surface resources with a lot of talking (theory and the like) it would be appreciated.

Original:

Thank you for the informative critique, I will work on materials in this respect… meanwhile, I am uncertain what I see with the first two images (or just one). I tried to recreate it but did not quite succeed. It looks like you subdivided it and moved the last edge inwards, but when I try to make additional cuts on a subdiv mesh it adds bumps or straightens a surface if it was curved; why is yours still smooth?

example of bump: http://pasteall.org/pic/index.php?id=111853

I gave a very distilled example. It’s not going to be the right move in every situation, and it’s kinda one of those things you will get a feel for with time.

Here’s an example on your model where this concept might be applicable. See where the door meets the rear quarter panel? The door has extra geometry causing it to round out more than the panel. This might look nice when looking at wires because the edges all line up. However, that panel needs extra geometry to support the same amount of curvature when smoothing.

As for tutorials, I don’t really know of any off the top of my head that cover theory. Though I’ve actually been thinking about doing tutorials on the subject in the future. I’m not saying I’m a master among masters, but I’ve gained a fair bit of knowledge over the years, yet by day I’m a P&C insurance agent. hehe Would be nice to put my knowledge back into the community.