Bei welchem Bildschirm-Maßsstab bzw. Planlayout-Maßstab ?
If you changed the scales in the option menu I mentioned then I don't know any other options sadly. It is because you can't make a diameter round 10 look like a diameter round 25 for example. The way with the option is to let it change the graphic view from a solid dot with a diameter of the rebar or an outer line round the outside of the rebar. With the last option you can make it look a little thicker if you set the bar in a sublayer with line thickness 0.7 for example. But again you can't fill in somewhere you want it to overwrite the diameter of the model with a certain scale.
Only other option I know is that you can give bars a scale factor so it will look bigger, also in the model. So if you give bars a scale factor of 2 all the bars will be shown twice as big. Not sure if you want that but maybe you do, so take a look at it I would say, see picture 1.
Maybe Jürgen has other options he knows of...
Kind regards,
Nick