XS_ZOOM_STEP_RATIO_IN_SCROLL_MODE
Category in Advanced options dialog: Model views
Use this advanced option to set the zoom
ratio when you are zooming by scrolling and holding down the middle mouse button at the same
time. Enter a decimal value. To zoom more with a single mouse scroll notch, increase the
value. The default value is 0.01.
This advanced option is user specific and the setting is saved in options.bin under the user folder, for example, in C:\Users\<user>\AppData\Local\Trimble\Tekla Structures\<version>\UserSettings. Restart Tekla Structures to activate the new value.