As aforesaid，when I use houdini on macos ，I found it’s unreachable that completed the operation that moving Viewscene through my trackpad.And homogeneous problem also occur in Network view——couldn't move view without middle click.
In gentle，the same operation of Houdini on Windows usually does with press the middle click of mouse，while Mac OSX system has not equip the function of middle click defaultly. I can finish all operation of viewscene transformation except moving the view across the screen space,which is very important for me exploits the function of houdini on macos.

I hope who can tell me the solution if I don't find the setting of Shortcut key setting , and if possible, I suggest we can finish the operation of scale viewscene by open our index fingers and thumbs.meanwhile, rotation viewscene by Move our thumbs and middle fingers in sync,and use three fingers to achieve the function of moving the view across the screen space,which is more logical compare with current setting.

I just use a regular mouse on MacOS with 3 buttons.

But there are solutions for trackpad users to emulate a middle mouse click, which I never tried myself

Check this:
https://www.tokeru.com/cgwiki/HoudiniUserInterfaceTips#Houdini_on_a_laptop,_middle_mouse_button [www.tokeru.com]