Scaling a part in SOLIDWORKS is an easy thing to do. However, did you know that when you scale a part, you are actually only scaling the part and not the sketch and constraining dimensions. Let's take a look. Notice the 245 mm dimension at the bottom of the picture. This is the sketch dimension before anything has been scaled.
To actually scale the part, you go to Insert, Features, Scale.
Once you select scale, you have a few different options on how to scale your part.
In this case, we will scale our part via the Centroid. You can see by the screen shots below that the part on the right has been scaled by 1.5 and the dimensions do not change. The part on the left is the original design.
The reason that we are showing you this today is because it can lead to some confusion. You may be expecting the dimensions to be scaled accordingly but that is not what the scale feature is intended to do. If you want the original sketch to be changed as well, you will have to modify the sketch and actually scale that. Here is the original sketch, but I can't scale it because of the dimensions. The trick is to set all of the dimensions to driven. Select all the dimensions and select other on the dimensions dialog box and set to Driven.
Once they are set to Driven, you can then scale the sketch and the dimension will update because they are not set to driving but driven. Notice the dimensions in the picture above versus the dimensions on the picture below. To scale the sketch go to Tools, Sketch Tools, Scale.
Hope this clears up any confusion and allow you to use other tools that SOLIDWORKS has to offer.
Field Technical Services Manager