Static Mesh Imported from Blender Missing Polygons

[LaBombaFrita]

This summer I've decided to practice creating custom weapons for UDK. I've built a basic gun model in Blender and have exported it to the .fbx format. However, whenever I import the model as a static mesh, polygons making up the butt of the rifle will end up not drawing. What seems to be weird is that whichever polygons seem to be missing depends on the viewing angle of the model.

Below are two pictures of the problem area modeled in Blender:

http://fc07.deviantart.net/fs71/i/20...ta-d6554ph.jpg

http://fc00.deviantart.net/fs71/i/20...ta-d6555dg.jpg

And below are screenshots of the mesh imported into UDK as a static mesh:

http://fc07.deviantart.net/fs70/i/20...ta-d6555yb.jpg

http://fc07.deviantart.net/fs70/i/20...ta-d65560z.png

Does anyone have any ideas what might be causing the problem? I'm new to 3D modeling, so I apologize if I'm leaving out important details. Thank you for your time and your help.

[Spoof]

The poly normals are most likely flipped. Blender renders both sides of a triangle, but UDK (and most engines) only render the front face by default.

In Blender edit mode, select everything and "recalculate normals" from the tool shelf on the left.

[LaBombaFrita]

I just tried your suggestion and it solved the problem. Thank you. Is there anything else I should know when creating static meshes and skeletal meshes in Blender?

[Spoof]

There's a thread "Blender and FBX" in my sig which gives an insight into the skeletal mesh workflow, and there are several more threads around for working with the various importers. Smokey13 had a long thread developing a vehicle mesh in Blender.

Static meshes are easier to get results, and its worth sticking with them until you're comfortable with the process. Skeletal meshes can be frustrating until you work out all the quirks and they are much more complex due to the skinning and rigging process.

[smokey13]

Smokey13 had a long thread developing a vehicle mesh in Blender.

understatement...

there is a direct link to my thread on my profile page, its not great but there is some good information, for example spoof gave me an in depth explanation on how smoothing groups can change the vert count of a model by a massive amount when you import (with example pics of my model with and without smoothing), witch is something you should definitely take into consideration when modelling. I think spoofs explanation is about half way down the first page.

also geodav explains pretty much everything you need to do to export from blender into UDK, and how to set things up in both, always worth watching his tutorials.

oh and recalculating the normals for whole meshes sometimes doesn't work and leaves a couple of faces flipped the wrong way and you will have to select the faces in edit mode and flip them manually.

[Spoof]

... its not great but there is some good information...

It's a fantastic resource for anyone building a vehicle from scratch, and it's all down to you and Geodav. If I ever get around to making a driving game I know where to start

[LaBombaFrita]

You guys are awesome. Thank you once again.

[SkyWay]

Just going to randomly pitch in here as I didn't see anyone saying this, but you can get Blender to not show 2-sided polygons by going to the Properties (N key) menu in the 3D view, there click on Display if it isn't open already and there tick the Backface Culling checkbox

[smokey13]

Just going to randomly pitch in here

your first post in two years is very random

that reminds me if you get the properties panel up in the 3D view (as skyway says) and switch to edit mode, scroll down the properties window to mesh display and click on the normal button it shows you witch way there facing.