Originally Posted by MrCATIA

Minhkhai,

I've never seen an option to change the display of sketch constraints (what you called "2D dimensions"). I'm thinking it might be either your graphics card, or maybe your computer settings. Try going to the Control Panel and Display Properties and change the Screen Resolution.

You can interactively change the size of the text in the Spec Tree: click the axis in the lower-right corner (this makes the tree active), zoom the tree to whatever size you want, and click the axis again to deactivate the tree.

hope that helps