I want my character on Prop Upper Surface allows. Such as I have a curve Prop and I want my character on prop surface allows. My character should keep his leg positioned as like my prop style.

If I understand correctly what you want to do, you would need to right-click the prop and select Convert to Terrain.

See manual: http://manual.reallusion.com/iClone_7/ENU/Pro/Default.htm#iClone_7/Pro_7.0/11_Set/Terrain/Create_Your_Own_Terrain.htm.

If you now have your character walking, he/she will now follow the surface of the prop.

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