23 days

I wrote this 23 days because yesterday i've watched 30 days.
Today another small learning process for me, i knew now how to check the drawing by looking at the number. Plus besides that, let just send the IFC first then use the time to do checking instead of do the checking then IFC that could take a long time, yeah.
I have learned also today about the material steel, concrete, wood mansory. Those material which would used as a structural material will be need to be strong and stiff. Strong means it can take good hard pressure and stiff means that it wont deflect too much under a weight. Steel is the most powerful in term of tension, while concrete is 1/10 of steel, mansory is 1/30 the rest is like a blur memory in my mind.