created walls not showing in 3d if i change Display style?

Hi all,

I am using AECOsim Building Designer Connect edition, I referenced 2D file and started to model 3D using Linear element to form. But after model if hit right click, it disappears. Please refer the attachment. I don't know whether its problem in installation or missed material library. And in the interval of 20 or 30 mins application getting shut down with the prompt (Aecosim Building designer stopped working).

Thanks in advance.

Regards

Akbar Ali k