You can use the 3D cutaway function to create a custom 3D cut plane in any direction Just turn on the 3D cutaway symbol and click the arrow to the right to select the Custom Plane option. Then hover the cursor to the element you want the cut plane to snap to.
Whether you loaded the Picture (frame) 17 object from your ArchiCAD Library 17 or you have it embedded from BIM Components, if you want to edit the image displayed for a custom picture, you need to embed the image to your project as a library part. (e.g. CADIMAGE.jpg) File>libraries and objects>library manager Go
If you are editing a surface color or a pen, you may want to have a range of custom colors in the palette. You must select the custom pen box and then edit it, finally click ‘add to custom colors’