Hi, I need create cross brace for my garden house project. But I did't know how

I make all parts, I could do it by trigonometry, calculate angles etc. But it will generate many collisions. It is some simple way how create braces ? More in screenshots.

Blue is brace what I need to create ( generate ).  I do not want make parts of whole sections because of calculations of material needed to build.

Or it is some way how to easy cut-off colision parts ?

thanks a lot .. and sorry for stupid question.