I've created some custom bricks to use with LeoCad.If you like using Gothic arches, please support my project at Lego Cuusoo!You can use these bricks in LeoCad to build Gothic churches or for whatever you like! (They might still contain some superfluous lines, but this is the best I can do. Sorry.)
To add those bricks to your LeoCad library, download and unzip them and put them into the Ldraw/Parts folder. Then open LeoCad > File > Pieces Library Manager > File > Import Piece and Import all the pieces you like. Then close LeoCad and open it again. The pieces should then be available to use.