gokhantek wrote:
Firstly sorry for English, I created curve wall use with section profile tool, and add curtain wall, curve wall and curtain wall intersect like on image, I want to trim these coloured part, but I do not want to cut from any part of curve wall, only cuting from curtain wall... How can I do this? (Thanks in advance)

Create paralel elevation to this, open it and :
Use Design > Curtain Wall > Boundary Editing in Section > Extract Boundary to Fill. This will create a fill that is in the same shape as the Curtain Wall Boundary. Now you can edit the Fill polygon using any of the applicable pet palette commands. This Fill represents the desired shape of your Curtain Wall Boundary. After editing the fill polygon, use the Design > Curtain Wall >Boundary Editing in Section > Redefine Boundary from Fill command, then click on the Curtain Wall. The Curtain Wall Boundary is redefined to match the Fill Boundary.
Delete the Fill and view your edited Curtain Wall.
Other Curtain Wall Editing Possibilities in Section Window
Activate the Fill tool and draw any shape on the Curtain Wall surface. Use Design > Curtain Wall > Boundary Editing in Section > Subtract Fill from Boundary, or Add Fill to Boundary. The Curtain Wall Boundary is modified accordingly.
See also Adding and Subtracting Polygonal Shapes .

Read Archicad help...press f1...there you have pictures too

--------------------------------------------------------------------------------