I have made an eye-shaped trinket model in Blender. The front edge of the eye is supposed to be flat. However, one corner appears to slightly bulge out, while the other corner appears to dent inwards. I tried marking the affected edges sharp, but that did not seem to help. What is happening and how do I fix it? Attached is a picture showing the model in Blender and then displayed in Poser.

Are you sure the vertices that join in those corners welded properly?

Prior to importing to Poser did you all your modifiers? If not I would look for verts that are not welded properly like LuxXeon mentions above

Everything seems welded properly. The Blender export options I have checked are: Apply Modifiers, Include Edges, Write Normals, Include UVs, Write Materials, Objects as OBJ Objects. Importing into Poser I checked only Centered and Place On Floor.

Playing with grouping tools in Poser, I was trying every option with which I was not familiar. Using "Create Perspective UVs" fixed the problem.

However, I don't know what "Create Perspective UVs" actually does, or what specific problem it seemed to fix.

I normally do not recommend paid products or tutorials since Blender is free but where Poser is concerned this product that is in our market place here and I happen to own it so I can personally recommend has allot of information about settings in Poser when deal with models imported from out side programs most are general modeling techniques you can use across different software and adjustments with in Poser that you may need to do so it looks right and currently it is on clearance price Modelling for Poser Both Poser and Daz Studio have their own oddities that make a model that is imported look wrong no matter that the model is perfectly fine. I know this might not fully answer your question but it is the best I can recommend. I also recall someone mentioning that at times Tris work better in Poser than Quads but I think that was truer for older versions of Poser And on a final note you can Create Perspective UVs in Blender I have seen free tutorials on that on Youtube

Good Luck

Oh, thanks for the tutorial link Lobo. I just went to check it out, and it's on sale for a very reasonable price.