Hello there!
I'm trying to make some new meshed clothes for sims 3.
I've read a lot of tutorials and managed to make new mesh,
I managed to package it with CTU and see it in CAS
but everytime I try to see it in game by moving my newly created sim which is
wearing my new mesh in some house in the neighborhood game crashes!
Can someone help me?

have you tried moving in a sim without your mesh on to make sure it's *that* clothing mesh that's crashing the game and not something else? Because generally if you're dealing with a bad CAS file the game would crash either when Create-A-Sim is loading or when you try to put the clothing item on the sim.

This happened to me one time when the base mesh need Lod1 and Lod1_1 and I join and export only Lod1 then game crashes when a Sim used the clothes, then I export Lod1 and Lod1_1 and the game don't crash.

Could be a missin Mesh file, even a lod2 file.
Does it imidiatly crash or when using zoom?

@ daluved1:
I didn't try to go in in game without sim wearing custom mesh!I'll try that!
I've also had in past tries that second crash,when I went in clothing category in CAS game just crashed
but then I didn't copy the comments in Milkshape to all the LODs!
Now it's just this crash left!
@ Kiara24:
Original mesh I exported with CTU are some short pants and they have 3 files
LOD1,LOD2 and LOD3!
When I created new package in CTU I've put my new meshes in LOD1,LOD2 and LOD3
but not in the LOD0 cause the original mesh didn't export that LOD!Is that ok?
@ Base1980:
It crashes the second I press the "Purchase" button on some house!
The game should then zoom-in the house but it crashes! :S

Anyone has a doubt where error is?
I'll explain you what I did so you can direct me where I have mistaken:
I've selected mesh I wanted to change in CTU and clicked on "Extract meshes"
There were four files:
amBottomShortsCargo_fatigues_lod1_0x000000005308CD07.simgeom
amBottomShortsCargo_fatigues_lod2_0x000000005308CD04.simgeom
amBottomShortsCargo_fatigues_lod3_0x000000005308CD05.simgeom
736884F1_00000001_0000000000E647C3.vpxy
Then I opened the first one(with LOD1 in name) with Milkshape using "Q-Mesh Sims 3 GEOM Exporter" plugin
I've changed its mesh a bit,copied everything in Comments in Groups tab,and exported it as a new simgeom!
Then I selected whole mesh,went to the Tools->DirectX Mesh Tools... and reduced number of polys or verticies or whatever they're called to the half!
Then I selected the whole mesh again and went to the Vertex->Align Normals and the blackness disappeared,
then I pasted the Comments,which I copied from the original mesh,
to the Comments in the Groups tab and exported this as a new simgeom!
I repeated this for the LOD3!
Then I went to the CTU and selected the original mesh which I was changing
Added new design by going to the Designs tab->Add New Design->Copy all from base,
then I went to the Meshes tab,changed mesh name,imported 3 new meshes
to the LOD1,LOD2 and LOD3 spots and exported this to a package!
That's it,where have I mistaken?

Yeah...I believe removing (or adding) vertices is a big no-no. The game uses a set number if vertices to make the clothing morph properly and when you're missing so many the game tends to go crazy.

Now I know having consistent vertex number was a big issue for some and I'm pretty sure that still stands

*Meshing for the sims 3 is pretty hard if you want to do it correct.
You can edit the lod1 meshes CTU extracts a little bit, move the vertices and delete stuff but you can not add new verts/faces/parts!!
The moment you want to add stuff you need to also update the morphs, renumber the meshes(vertID's) and make new Bgeo files wich you then can import into your package.
*The directx tool is pretty much useless when it comes to reduce the polycount on outfitmeshes.
Altho it works great on reducing the ammount of faces you will lose all bonesettings for every vertice when using it. And reassigning a whole mesh with new boneassignements is very very hard!!

And you can NOT convert a lod1 mesh into a lod2 mesh!!!
Both meshes have difrent bonesettings/diffrent vertID's and diffrent morphs

Use Directx tool on hair, accesoires or(when you do know how to reassigne bones) shoes.

So you can edit your mesh a little bit and reload the lod1 file.
Make the same edits on the lod2 and lod3 meshes.

Explaining how to make new custom meshes will take me some time....wich i do not have.

THAAAANKS!!!!THAT WAS VERY HELPFUL!It finally worked!!!
Can you tell me where LOD0,1, 2 and 3 are used?
I know that one of them is used for portrait picture,
one when you're zoomed out in game,
I guess that LOD0 would be the one we see in CAS,
and I guess that LOD1 is used in game when we are close to the character(aka not zoomed out)
Am I right?

There are packages with Lod0/lod1 and lod2 and there are packages with Lod1/lod2 and lod3 but both have the same order:
High detail/medium detail and low detail.

Lod0, lod1, 2 and 3 are used ingame
At close range the game uses the high detail mesh Lod1(or lod0), zoomed out the medium detail mesh lod 2(or lod1) and zoomed far away the low detail lod3(or lod2)
The mesh you see in CAS is also lod1, or lod0 when that one is used as high detail mesh.

The combination Lod0/lod1 and lod2 is often used for accesoires
The combination Lod1/lod2 and lod3 is used for clothing

Wow,thanks! :D
Your information was very helpful!
I can't thank you enough!