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I am trying to render a set of lines through an OBJ file and the matching MTL file. The import does not give an error and the MTL seem to be correctly imported. But the render image is empty. I am a noob to blender and any help is highly appreciated. I have attached the links to the files below. Thanks.

MTL: https://drive.google.com/open?id=0B-TWCTRv7UM1VTl4SWo2Zy1ZYmM

OBJ: https://drive.google.com/open?id=0B-TWCTRv7UM1TWdJREQzWnE2NFU

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Your object only consists of connected vertices, it does not have any faces.

Blender needs faces to render an image.

no faces no image

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  • $\begingroup$ The object is a set of lines. If I delete the MTL file links from the OBJ file, I can add a single color to the whole object and render that. Also, if I put a environment light, will it help? $\endgroup$ – ssm Oct 25 '16 at 22:57
  • $\begingroup$ As I said, you need faces to get something to render. Vertices and lines aren't enough. Try it. Take the cube of the default scene, go to edit mode, hit "A" to select everything, then "X" and select "only Faces". Add a material and try to render that. Nothing will appear. No faces, no geometry to get light bounces from, no image. $\endgroup$ – metaphor_set Oct 26 '16 at 0:37
  • $\begingroup$ Hi, I can get something to bounce light if I select the material as wire. Am I wrong? And I can render that and get a color. $\endgroup$ – ssm Oct 26 '16 at 13:08
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I was able to get a render out of the OBJ and MTL file finally by following the folowing steps. Granted I had to modify the OBJ file tool. OBJ modification: Add g mtl_i above each usemtl mtl_i line.

I also used the following script in blender to change material properties.

for i in D.objects:
    if i.name.startswith('mtl'):
        i.active_material.type='WIRE'
        i.active_material.use_transparency=True
        i.active_material.alpha=0.4
        i.active_material.transparency_method='Z_TRANSPARENCY'
        i.active_material.use_shadows=False
        i.active_material.use_cast_shadows=False 
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