Hello,

This is a very interesting request:
We have it a lot and i will say, there is a lot of solution but not that automatic.

1°) you can modify the display of your reinforcement bars manually by modify the property. (manual work for each bars.) You can hide the bars in the object palette to change other.

2°) you can create 2 view on top of each other. So one view will contains the bars which must be display and the second view will be the bars in grey. It can be a setting of the view but i'm not sure the bars will be grey. Still, you can modify them manualy.

3°) sometimes, i export all the reinforcement in 3D (from reinforcement to 3D) in a separate drawing file. Than i convert the format to grey color. And at the end i add the model in grey color to my view with real reinforcement.

4°) If it's okay for you to don't see the display in the construction mode, then you have some possibility in the layout editor. You can place 2 view on top of each other from 2 different drawing file.

Than in the layout editor, you can set the grey color on reinforcement in back ground from another layer.

This working quite well.

Have a good use!