Set extents for zoom extents with modelspace

[glennQUAXD]

Is there a way to set the extents within modelspace to control the maximum view size when using zoom extents?
I often work with large plant layouts created with global coordinates. These layouts often have other infrastructure, (roads, contours, boundaries) within the model, located hundreds of kilometres away, but I only want to zoom to the localised plant that I'm working on at the time. If I use zoom extents, I lose my point of reference, as it zooms too far out. Sometimes beyond a single pixel. I've tried limits, but this doesn't seem to control zoom extents within modelspace. Microstation has a similar variable which restrains working model area.

Kind regards
G

[Gabriel_Watson]

Use Zoom to Object:
Z + ENTER + O + ENTER, then pick a box you may define as an area of interest.

https://help.autodesk.com/view/ACD/2024/ENU/?guid=GUID-66E7DB72-B2A7-4166-9970-9E19CC06F739

[glennQUAXD]

Thank you for suggestion.
I forgot to add the problem exists when changing 'UCS' 'plan' 'current or enter'
This then zooms to extents automatically - perhaps there is another work-around for this part?

[Gabriel_Watson]

"Type UCSFOLLOW in the Command line, and press Enter.
You will be prompted to Enter new value for UCSFOLLOW.
Type 0, and press Enter. Your UCS should no longer zoom to extents automatically."

Found here:
https://www.landfx.com/kb/autocad-fxcad/view/item/2277-ucs-zoom-extents.html

[glennQUAXD]

Thank you for your response.
UCSFOLLOW was already set to 0.

If you rotate a UCS to align with an object, then 'zoom' ' plan' 'current' it will zoom square to current UCS, but also zoom to extents of whatever is in the drawing, including xref's or distant objects. 
Unfortunately, your response does not restrict the extent of the zoom-out function, which is the crux of the problem. We need to find some way of restricting the zoom 'extents' to a selected smaller window/boundary and leave this selection set at the users discretion. Then regardless of UCS commands or other, when we do a zoom all or zoom extents, we only zoom to the pre-set boundary. 
Microstation has a similar property called drawing limits (I think that's what it's called), where the drawing boundary can be set to say 5 km. Anything outside this is not visible and zoom extents then only goes to the set 5 km x 5 km x 5 km boundary. Tekla also has a limits setting.

A similar example of where this function is necessary is working with point cloud data. The file becomes too large to work with in plant design / point cloud scans. We need to be able to restrict the file or zoom to say a 100 x 100 m x 100 m boundary / limit / extent. Then visibility, calculations, graphics or zoom functions only operate within this boundary.

Is there anything like this available within AutoCAD, AutoCAD Plant 3D or even drag files into Civil 3D, slice and dice and then bring back into plant 3D?? Desperate for help. It's a real sticking point for us and causes a great amount of inefficiency.

Kindest Regards
Glenn

[RobDraw]

By definition, zoom extents is determined by the objects in the view. Anything less wouldn't be the extents. 

I would utilize working through locked viewports in a model with large extents.

[Michiel.Valcke]

With the command _LIMITS you can set limits to your drawing by determining the lower left and the upper right corner. You can save this information in your drawing template. Then if you use the below code you will zoom to your set limits and not to the extents of your drawing.

(command "_zoom" "_w" (getvar "_limmin")(getvar "_limmax"))

You can put the code under a command button in the CUI and add the button to your ribbon/Quick Access toolbar.