i m using caesar2 and in relation to this but also in general i wanted to ask what is the difference btween a butt weld Tee and a welding Tee (i m totally new in this domain), thank you for any help.
There is a specific Caesar forum under Engineering computer programs. However to answer your question as best I can - a butt weld tee is a simple tee which has pipes butt welded onto it, normally with dimension as per ASME B 16.9. A welding tee is a bit vague and could either be the same thing or just a pipe with a hole in it and another pipe attached using welds and possibly some sort of compensation plate. This would be as per ASME B 31.3. You should ask on the Caesar forum and see if anyone knows there.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way