UV mapped textures turning black

[Albi]

Hello, I have problems exporting DirectX files with Blender:
with the last exporter I have tried to load in mine programs some DirectX armature animations UV mapped and with automatic skinning made with blender with good results except that strangely now and then the mesh turns black, then it is sufficient to move a bit the mouse pointer and it returns normally textured but after some time of good working the turning black mesh problem returns
this happens only now and then but is rather annoying in a game
what may be the cause of this texture turning black problem?
This is the more serious problem I have had but I have got a minor one also: curiously it seems I must multiply the frame numbers in setFrameLoop by a factor of about 200: this is an example of what I have done in the following code fragment
Considering that in Blender my Gus animation has 40 frames only somebody knows what may be the cause for this?

mesh_pupazzo = smgr->getMesh("media/Gus.x");
nodo_pupazzo = smgr->addAnimatedMeshSceneNode( mesh_pupazzo );

if (nodo_pupazzo) // If pupazzo exists
{
nodo_pupazzo->setScale(core::vector3df(60, 60.0f, 60));
nodo_pupazzo->setPosition(core::vector3df(pupa_x, pupa_y, pupa_z));
nodo_pupazzo->setMaterialFlag(EMF_LIGHTING, false);
//To play the first 20 frames: nodo_pupazzo->setFrameLoop(200, 4000);
//To play all the frames:
nodo_pupazzo->setFrameLoop(200, 8000);
//the triangle selector for pupazzo
sele_pupazzo = smgr->createOctTreeTriangleSelector(mesh_pupazzo->getMesh(0), nodo_pupazzo, 128);
nodo_pupazzo->setTriangleSelector(sele_pupazzo);
sele_pupazzo->drop();
}

[Guest]

W.r.t. your second issue: Irrlicht seems to use milliseconds as the frame numbers.

If you have e.g. a 25fps animation, that means every frame number in the modeling package needs to be multiplied by 1000/25=40.
If you need a factor of 200, my guess is you're probably using a 5fps animation in Blender.

[Albi]

W.r.t. your second issue: Irrlicht seems to use milliseconds as the frame numbers.

If you have e.g. a 25fps animation, that means every frame number in the modeling package needs to be multiplied by 1000/25=40.
If you need a factor of 200, my guess is you're probably using a 5fps animation in Blender.

I thank you for your kind help, I was using a 5fps animation in Blender indeed, then things must be as you say, so you have solved my second issue

[Albi]

Hello, I have just made a little experiment: if I load Gus mesh without any texture I obtain a quite white Gus that now and then becomes quite black
then changing just a bit the view point it returns white
somebody has got some idea what may be the cause of this texture turning black problem?