While making meshes, I checked animation in Create-A-Family screen - assumed that it gives me pretty good impression on mesh animation. As I thought I'm almost done, I tried to test more thoroughly in game, and what I saw with 2 of meshes made me think I'm hallucinating Screenshots attached. Any ideas on what's going on and how to fix?
I'm sure that I didn't move any bones.
I'm sure that bone weights for distorted areas are much close to original mesh weights.
In child mesh, bone assignments for left and right arm are symmetrical, right arm is distorted, left is not.
For teen mesh, there's male kimono made from the same mesh with only few vertices moved - and it doesn't has those weird spikes over face.

What confuses me the most is how could it be that sim in the same or almost same pose looks different in Create-A-Family screen and in game.
Any ideas, anyone, please?

I have had a similar problem happen, but the opposite way. A mesh I made had a very noticable "point" showing near the knee when seen from certain angles on Create A Sim screen but I could find nothing wrong. I tried it in the game, made the Sim do every animation, closely looked from every angle, and never saw the spike in the game. So, I think the animations used on Create A Sim are not exactly the same as in the game.

Do you see any difference in the arms in BodyShop? If a joint was moved, it will cause a very obvious warping of that part in BodyShop.

I also have found a very strange thing about testing in the game - if I put a new mesh on a Sim in my game and see a mistake - I quit the game and go fix the mesh and put it back. Then I start the game again, and go back to look. My Sim is still "wearing" the old mesh, nothing is changed! I have the Sim go take off these clothes, then put them back on - now the Sim is wearing the new mesh! Could this be what happened to you?

If not, go back and check to be sure there are no underweighted bones in your mesh.

Also there are some joints in the skeleton that are never used for vertex assignments, make sure none of your vertices are assigned to those. Compare with an original Maxis mesh to be sure.

Actually, I begin to suspect that it's something with my game now - I asked a friend to try these meshes in game and she saw no distortions :-\ I have original game only, she has all addons, but I doubt it can be the reason. Will check with another friends
Anyway, Dr Pixel, thanks for your ideas
In Bodyshop, it looks the same as in CAF.
No assignments to 'unreal' bones, I'm attentive to those.
I think it's not the case - I used brand-new family created days after last change to these meshes was made. Thanks for the note anyway - I'll keep it in mind when test new meshes
I use Max, not Milkshape, and it auto-corrects weights to have sum=1, as long as particular checkbox (Normalize) is checked. It was Anyway, I checked weights for all doubtful areas (Max can show weights for selected vertices and all affected bones) and saw nothing suspicious.

Make sure you are only using 3 bone weights if you only have TS2 base game. I think 4 is not supported until Nightlife?

Yes, that is correct - but I think the only parts that have 4th bone weight on Maxis meshes are some of the fingers?

Another thought - it is also possible that a joint somehow got "rotated".

It could still be in the exact correct location, but rotated in some direction - probably the joint near the shoulder. The joints should all come into your 3d editor at the "zero" position and must be sent out again in that same position.

In MilkShape you could check this by comparing the numbers in this bone's "comment" section with the numbers of an original Maxis mesh.

In 3d Max I don't know how you could check this, but there must be a place where you can determine the rotation value of the joints?

Just tested it in the original game. The only problem I could still notice is that the sims' heads looked "separate" from their bodies.