I am getting a warning “WARNING- TD or TB IS ZERO IN USER TABLE …” What are these values ?

When a user table general section is defined, the software needs to know what thickness ( t ) to use to calculate the D/t or b/t ratios where D is the section depth and b is the flange width. This information is necessary for classifying the elements of the cross section like webs and flanges during the design phase. TD is the thickness associated with the depth or in other words an equivalent thickness of the web that can be used for classifying the web (used as t in D/t). TB is the thickness associated with the width or in other words an equivalent thickness of the flange that can be used for classifying the flange (used as t in b/t). Since user defined sections could be of any shape and form, it is not possible for the software to find out what value to use for these terms and so these are left as zero and a warning is generated to make the user aware of it. The user needs to input appropriate values for these items.