7 replies to this topic

[Reegan]

ok, so i managed to write some code that would read OBJ files ( to an extent ) so i tried to see if the values i was loading in from .obj file would indeed form the mesh created in my 3d package, i created a simple cube and exported only the vitals ( vertex positions and faces ) then loaded it into my small application ( faces being the indicies loaded into the IndexBuffer ) only to find out that the cube looks nothing like it did in the 3d package * shock horror * So i thought, "ok, must be some setting somewhere i messed up.." - hour later - i decided to take a look inside a .x file and compare it with the .obj files data, vertex positions are roughly the same the except the Z components in the obj file are the inverse of the Z component in the .x file ( easily fixed when loading the data ). But the faces in each file are completely out of whack with eachother!! whats going on here? i tried googling around and to find some tutorials on loading obj files in directx but didnt find anything of use. perhaps someone here can explain what i have to do to get the correct faces, and ultimatly a good looking cube [smile] i tried: - changing options in the exporter - changing the primitive topology - swapping the Y/Z - googling.. - and some other stuff... Thanks in advance ~Reegan [Edited by - Reegan on March 23, 2009 2:33:01 AM]

[Geoffrey]

Quote:

Original post by Reegan the faces in each file are completely out of whack with eachother!!

How do they differ?

[c00ler]

Hi,

There's a sample integrated in the DXSDK wich show you how to load .OBJ in your DX scene :

C:\Program Files\Microsoft DirectX SDK (November 2008)\Samples\C++\Direct3D10\MeshFromOBJ10

Good Luck

Peace

[Evil Steve]

Have you tried disabling culling (pDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE))? It may be that OBJ files store their vertices in counter-clockwise order; especially if Z if flipped. If that fixes it, then try changing the order of your indices (From {1, 2, 3} to {1, 3, 2}).

[Reegan]

Hi, thanks for the replies ive tried what you have all said already, no luck [sad]

Here are the two exact same cube mesh files ( in *.x and *.obj ) with there differences. I dont know alot about indicies so i cant really figure what should go where.. maybe you guys can figure this out?

*.obj

Quote:

# # object Box01 # v -1.00 -1.00 1.00 v 1.00 -1.00 1.00 v -1.00 -1.00 -1.00 v 1.00 -1.00 -1.00 v -1.00 1.00 1.00 v 1.00 1.00 1.00 v -1.00 1.00 -1.00 v 1.00 1.00 -1.00 # 8 vertices g Box01 f 1 3 4 f 4 2 1 f 5 6 8 f 8 7 5 f 1 2 6 f 6 5 1 f 2 4 8 f 8 6 2 f 4 3 7 f 7 8 4 f 3 1 5 f 5 7 3 # 12 faces

*.x

Quote:

Mesh Box01 { 8; -1.000000;-1.000000;-1.000000;, 1.000000;-1.000000;-1.000000;, -1.000000;1.000000;-1.000000;, 1.000000;1.000000;-1.000000;, -1.000000;-1.000000;1.000000;, 1.000000;-1.000000;1.000000;, -1.000000;1.000000;1.000000;, 1.000000;1.000000;1.000000;; 12; 3;0,2,3;, 3;3,1,0;, 3;4,5,7;, 3;7,6,4;, 3;0,1,5;, 3;5,4,0;, 3;1,3,7;, 3;7,5,1;, 3;3,2,6;, 3;6,7,3;, 3;2,0,4;, 3;4,6,2;;

the .x file one works all i have to do is plug in the values into the vertex and index buffers and voila! but the .obj is seriously messed up.

Any help here?

[Dancin_Fool]

The indices in your OBJ file start at 1. The indices in your .X file start at 0. Just subtract one from each index as you load it in.

[wodan]

Looks like the only difference is, that the indices in your .obj file aren't zero based. The order is the same though.
Try to subtract 1 from each index when you load it.

EDIT: man, am I typing slowly!

[Reegan]

Holy **** it worked! thanks alot guys! how strange that .obj files start at index 1 :S, im going to check the mesh from obj tutorial and see if they subtracted 1 from each index or not.

wooooo *is happy now*

EDIT: They do aswell [smile] good stuff.