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I am setting up a simple scene with only a single object, a truck, and a point light. It seems that regardless of where I put the light, the hood (among other portions) of the truck won't be lit. Here's an example:

enter image description here

My first thought was that it was a problem with the materials on the truck. But the material on the hood is the same as that on the top and sides, so I don't think that it is the issue.

I also replaced all of the materials with the default one (diffuse intensity 0.8 and specular intensity 0.5) to see just the contribution from lighting more clearly:

enter image description here

Is there some other reason that might be making it impossible to light certain portions of the object?

Other possibly relevant information: In the images above, the light is a bit above the driver's seat of the truck, but the problem remains even if it is directly on top of the hood. I have had better luck with Hemi lights, but would prefer to use point lights if possible. I am using Blender Internal rendering. I am also happy to post more images (the car rendered with shadeless textures, the actual blend file, etc) in the follow-up.

lambertian
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    Check the normals of the model – Duarte Farrajota Ramos Jan 03 '17 at 05:16
  • Move your light away form the object to get better coverage... if you want your model to look better consider adding a very very big light source. Lighting cars is an art. See this link to get a few ideas: http://www.zacuto.com/how-to-light-a-car –  Jan 03 '17 at 05:29
  • @cegaton: Thanks for the suggestion. I tried moving the light away from the model and making it a bit brighter, but I still am unable to light the hood: example rendering here. – lambertian Jan 03 '17 at 09:10
  • @DuarteFarrajotaRamos I looked into the normals a bit, and found that Mesh -> Normals -> Recalculate Outside did change the shading a bit. Here's the new result. Much of the truck is still completely unlit though. Could you point me to a resource explaining how to deal with the normals better? – lambertian Jan 03 '17 at 09:25
  • If anyone would like to take a look directly, here is a download link to the blend file. There are only three objects in the file: the camera, a car, and a point light. The car has been decimated a bit to reduce the file size, but I don't think that shouldn't affect the lighting issue. – lambertian Jan 03 '17 at 09:35
  • Your model seems to have some shading issues beyond a simple one-button-press fix, was this modeled in Blender? I can only take a look at the model later tonight if no one beats me to it. – Duarte Farrajota Ramos Jan 03 '17 at 16:27
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    @DuarteFarrajotaRamos No, I imported an obj file from Shapenet, so I can't be sure of its origin or how it was modeled. – lambertian Jan 03 '17 at 22:58
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    Taking a look at your model, it was clearly made in a CAD-like solid modeling or NURBS base software. It has very messy geometry and awful topology, there are sever normal and shading problems that cause these artifacts. I don't think there is any simple one-click-fix for this, other than manually cleaning up. Add an Edge-Split modifier to the whole car, then separate mesh by chunks with Ctrl+L > P > Selected, and recalculate normals afterwards. It seems to be producing some mild results, though it doesn't completely solve all problems – Duarte Farrajota Ramos Jan 04 '17 at 01:34
  • I'd say it's because of the normals split in a custom way and imported with the mesh, https://blender.stackexchange.com/questions/76513/strange-black-shading-cannot-fully-light-mesh-cycles – Mr Zak May 29 '17 at 21:13
  • I believe the light is too close. The Dark areas of the truck are shadows from the lit areas of the truck. – Dontwalk May 29 '17 at 19:40

1 Answers1

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While im not a Pro. I Think, I THINK. You should try increasing the strength of the Light. Or try using multiple lights. I Could also say Try to Transparent the background and Raise the color of the background to a bright color Preferrably a Bright White This will make the Background transparent, And the objects in the rendered image will be Nice and bright. If you want to have the background grey i won't reccomend the latter.

One of my renders of a character for one of my games. With one default pointlight just above the head, Not bright, I Would like it more bright. enter image description here Now i have changed the Strength of the Pointlight to 900. As you may notice the ribs are more bright And so are alot of the other parts.

enter image description here

Trovian Jack
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  • I tried increasing the strength of the light (to 1000) and making the background white. Here is the result. It seems that the areas that were previously lit are now brighter, but the areas like the hood which weren't lit at all still are completely black. – lambertian Jan 03 '17 at 09:06
  • You didn't make the background transparent. – Trovian Jack Jan 03 '17 at 13:02
  • Good catch, thanks. This is the version with a transparent background. It unfortunately didn't seem to affect the shading on the truck much though. – lambertian Jan 03 '17 at 22:54
  • Hmm, Try to send me one with the background brightness lower Still transparent. If it doesn't work then give me the link to the truck and i will show you my attempts. – Trovian Jack Jan 04 '17 at 01:07
  • Here's the transparent version with darker background. If you'd like to take a look at the model directly, here's the folder with the obj and mtl files, and here it is imported and joined in a blend file. – lambertian Jan 04 '17 at 03:51