I'm scratching my head trying to figure this one out. I got a car file from sketchup warehouse and saved the 2020 version of the sketchup file. I opened it up in sketchup and exported it as a .obj file. I tried importing the .obj file into Poser 11.3 with the unsatisfactory results show in the attached file. I thought Blender might be able to clean up up so the model would show straight sides instead of the bloated sides (indicated in the red circles of attached picture). Does anyone have any ideas why this is happening and can anyone suggest a work around for me. Thanks for any help. Radar_rad-dude.

Try to lower the Crease Angle. You can find it in the Properties Tab of the object.As default it's set to Smooth Polygons and a Crease Angle at 80.
Usually i just Untick the Smooth Polygons all together when making someting like that.

I was just going to suggest unchecking the Smooth Polygons option as well. I have found I prefer to have Smooth Polygons set for my render options, so having them set in both places often blows up all, or parts, of an object.

You could try to change the vertex order at that polygons. Or if posible try to bevel edges for stabilisation of the polygons. And of course deselect polygon smoothing and lower the crease angle. A value of 30-40 may bring good results.

Since the car was from sketchup, what does the geometry look like? I've found it doesn't always export well.

Thanks to everyone that commented! I don't know what the geometry is in sketchup. I have had several models turn out quite nicely from there. Here,I lowered the crease angle to zero an turned off smoothing. Attached are the results in poser. The other image (smoother) is how it renders in blender. As you can see, I still don't have the result I would like. Any further suggestions are greatly appreciated!!!

In Poser, change the display to Hidden Line then post a screenshot of the model. As RedPhantom says, meshes made in CAD software don't often convert to polygonal meshes very well. Also, is your Poser image a screenshot of the Preview window, or a Firefly render or Superfly?

The poser image was rendered in Firefly.

A problem with vertex order might cause Poser to calculate incorrect normals which would explain the banding effect. IIRC there is an option in Firefly to force normals to outward.

Poser do prefer quads on the mesh and elongated tris are not very favourable to have.

Things I can think of - first, try converting the mesh to quads in Blender (I believe there is a command to do that but I don't use Blender so can't be any more help there).

I have seen this kind of shading issue occasionally when I've been modelling in another app, and the solution there was to delete the vertex normal map. When exporting from Sketchup as OBJ, is there an option to preserve normals? If there is try exporting with it on and off, see if there is any difference. (I believe that Poser should ignore normals if they are in the obj and calculate them itself, but still worth a shot.) If not, try exporting from Blender in case there are more export options for OBJ.

When importing OBJ files to Poser there is an option to 'Make polygon normals consistent'; try importing with this on and off to see if it makes any difference. You could also try using FBX as the file format just in case that makes a difference (the current beta of Poser is up to date with FBX format).

A last possibility is to try adding one level of subdivision as this will create new geometry, but as the mesh has not been built for subD it probably won't work well ;)

Thank you all for your fine suggestions! I will get to work on them and see what happens. Have a great day everyone! Again, many many thanks to you all!!! Radar_rad-dude

I found a solution, I think, that gives me almost a satisfactory file for poser. I exported the sketchup file from sketchup as an fbx file. Then imported it into blender and exported it from there as an obj file. I have to do a lot of tweaking to the file now but at least it looks like it smoothed out the bad areas and does give me something to work with. Thanks to everyone for their excellent suggestions.