c++ - FBX model's faces (some) are not rendering properly -

i've created basic sphere in maya , loaded opengl project. problem i'm having shown below:

as can see, sphere triangulated.

but when model loaded project, of faces aren't rendering properly.

these maya fbx export settings (checked):

general options - default file extensions - preserve references

current preset - user defined

geometry - smooth mesh

convert nurbs surface to: - software render mesh - referenced containers content

embed media - embed media

units - automatic

axis conversion - axis: y

ui - show warning manager - generate log data

fbx file format - type: binary - version: fbx 2013

any ideas why happening? i'm using fbx sdk 2013.

edit:

didn't realize @ time of posting white triangles (labeled "bad triangles") appear due simple light rendering. extended bar on right actual problem.

saw question on youtube video.

it looks me of triangles being culled out on extended bar. maybe of triangles on bar have incorrect winding? check for. check winding on triangles , play around opengl cull face.

as shading, i've seen resembling before. looks may need enable smooth shading, instead of flat shading. try calling glshademodel(gl_smooth);

also try calling gldisable(gl_texture_2d). if texture enabled , appropriate texture coordinates not given, can result in weird flat shaded triangles you're seeing.

the other possibility can think of normals not set up. here few reasons happening:

1. you did not export normals.
2. you did not import normals vertex buffer objects, or cache information
3. your shaders (assuming you're not using immediate mode) not reading or processing normals correctly.

hope helps. luck!