again me i made an alpha mesh again and it looks like that how can i fix it :D

It will always look like the second picture, its almost impossible to eliminate the clipping.
Its caused by the way sims walk, they actual step over like a model on the catwalk.
You can cheat a little by putting the legs a bit wider and give the inside of the legs also some boneassignements from the opposite leg.
Here's a mesh that comes close:http://www.insimenator.net/showthread.php?t=75350
The skirt is much longer then viewed on the screenshot.

The first picture is prolly a duplicate face/s.
Never give a skirt inside textures unless you absolutly sure it works properly.
If you start by giving it inside texture and you need to split up a vert by using divide edge you ruine it all.
Make sure you have only a skirt with outer faces!

thnks i'll try

i did skirt but foot isn't change or it changed little

If you want to keep the skirt flowing ahead of the model, use some weighting from the pelvis.

You might think about just eliminating the feet and legs altogether. It looks like you would never want to see them, and unlike real people sims can walk with invisible legs.

<* Wes *>

i used auto joint but still same
i'll put new pictures you can understand well thnx for help

Dont use autojoint!
If im correct this is only in a experimental fase and will do worse then good to the original bodymesh.

Like Wes said, assigning it partly to the pelvis will prevent it from moving to strong with the legs.

i did so (use partly pelvis) bu it isnt work

here i used autojoint (i didnt use autojoint in previous pictures)it's better with autojoint then witout autojoint but still there are little problems

It will always clip at the calves, i told you why.
The reason that it works better with autojoint is because it gives the dress and the legs the same boneassignements but you can not used it as you will lose all 3 bone assigned vertices giving you a animation you dont want.(unless Wes updated, but i dont think so?)
Check the shoulders and breasts, they should have a 3 bone per vert assignement!

Also make a outfit with the uvmap of the dress on it so you can easily find the areas you need to adjust.

No offence here but,
We gave you the advice to assigne it more to the pelvis.
If i need to do this with a mesh of my own it will take me several hours before i will have a proper animated skirt.
You posted a hour after you got that advice and said you tried but that it didn't work.
Alpha's are very difficult to get them perfect, keep trying

how can i be animation i think it's very difficult

yes, it is very difficult
One of the first things i do is to use the uvmap as clothing.
Extract the uvmap and put it on the dress.
Then you know exactly were to look and wat parts to adjust.

I haven't tried this, but I think it would make sense to line up the vertices on the dress with the vertices on the legs on the Y axes and then to make sure the bone assignments are identical or similar (where there are logical reasons for adjusting them).

The bend at the knee, for example, would be influenced by the position of the verts as well as the distance from the verts above and below them.

Just a thought.

yes, thats the way i have build all my dresses.:D

But this dress does has a total diffrent shape to do the same but is wide enough to use the pelvis boneassignements.
Take a look at a few child dress meshes, they animate with alot pelvis assignements.

i have this problem (i edited my first message)

wats wrong with it? looks ok to me.
You can delete the bottomfaces, you do not need to close a alphamesh at the bottom.

problem is that i think legs doesnt appear but i can see everything front alpha mesh

just delete the bottom faces first, i think it will lighten up then on the lower half.