The default 0,0,0 origin for underlays on reference planes is located at the center of the inserted underlay image.
Default Location of Underlay at Center of Page
It would be very useful to be able to custom place the Origin of the underlay to the Reference Plane's 0,0,0 Origin so that subsequent "revised" images have a known reference point. This is important so that future revised images can be stacked in the same known location. Examples are revisions to floor plans, lighting plans, furniture plans, stacking of floor plans on multiple stories and site plan revisions.
Example: Floor Plan with Bottom Corner at Reference Origin
[Note: The above image was done using the Billboard tool. The downside of the Billboard tool it doesn't allow you to adjust transparency of the image like the Reference Plane Underlay or Autocad's Transparency command]
The only way to do this currently is through the Reference Plane Parameters dialog box > Underlay > Custom Placement > Origin edit boxes for X, Y, Z. I believe I've discovered a bug.
I find it impossible to located the corner of a floor plan by entering values corresponding to the reverse values found in the Input Palette X, Y, Z edit boxes.
Example: Error Placing Underlay Bottom Floor Plan Corner - minus 14'-10 5/32" becomes minus 14'-10 5/32" + 29'-5 11/16" along X-axis.
1. Add a toggle "Click point to move to reference plane origin" (Less wordy perhaps) in other words, allow user to click a point on the underlay to move underlay to the reference plane's origin.
2. Permit the Underlay image to be selectable and movable similar to the Billboard Tool.
3. Add a transparency slider to the Billboard tool similar to the Reference Plane Parameter slider.
Edited by Paulji, 28 January 2017 - 05:27 PM.