Ensure that you have the backface-culling mode correctly set. i.e. are the faces/triangles specified in clockwise or counter-clockwise order? Set the culling mode accordingly.

With backface culling turned off DirectX renders both sides of a polygon, so the tiger would look fine, but there''s some unecessary rendering taking place, because the insides of the tiger will also be rendered, so if you position the camera inside the tiger you should see the "skin" around you.

If backface culling is on, only one side of each polygon will be rendered, and the polygon would be invisible if viewed from the other side.

In your case the backface-culling mode was set to the opposite of what it should have been, so the polygon-sides that should have been "front sides" (the outside of the tiger), were treated as "back sides" by DirectX (and were therefore not rendered), consequently the polygon-sides that should have been "back sides" (the ones facing into the tiger) were treated as "front sides", and were being rendered. Just set the cull-mode to the opposite of what it was and it should look right.

Whether the model should be rendered with CW or CCW culling depends on the modelling package used to create it (and how the model was saved). From the little I''ve seen it seems like CCW is the most common (I have no backing what so ever for this statement, just an impression I get). Of course you can always reverse the vertex-order at load-time should the need arise.

I''m not sure this is such a good explanation. If you play around a little with the cull-mode for different models you should get the hang of how it works.