3D items keep getting scaled up by 1000

[!AjI!]

Frustrating one this.

I have a drawing that is basically a number of 3D path extrusions of a circular shape to form some pipe runs.

They are drawn in modelspace at 1 unit equal to 1 metre.

The drawing is saved.

On re-opening of the drawing the 3D extrusions are now 1000 times bigger. Sitting at co-ordinates "1000 times away" from their intended location.

What is causing this?

(to further add to the problem Civil 3D locks up when trying to re-scale them by 0.001 back to the intended size and location)

[Udo_Huebner]

Aa sample drawing could help.

[!AjI!]

Apologies, I can't send the drawing as it is a sensitive Engineering site design that I am not permissible to share outside the project team.

Basically, an example drawing probably wouldn't be of any more use than the description of the problem in the OP.

The issue is as described, I have some 3D extruded path shapes that are placed in to real world co-ordinates and size, the drawing is then saved (v2020 DWG format), the drawing is then re-opened and the 3D extrusions are now at 1000 times their size and position.

It is as if the drawing is opened with a x1000 units setting. 

Checking the drawing properties from within Toolspace-Options, I see indeed that the drawing units are now at millimetres. But simply setting this back to metres doesn't solve the issue, because the 3D extrusions still remain at 1000x upscale at their 'new' co-ords.

The only way I can get the objects back to their correct size and location is to scale by 0.001 at a origin of 0,0

And the problem with that is each time I do it the drawing freezes up for about 20 to 30mins (or crashes).

[AllenJessup]

Is it possible that you have a Reference Template attached and that the units in the Template have been changed?

[!AjI!]

Would a reference template do that to a drawing after it has been saved?

I always understood drawings to open from a template, but then the template would not override anything that has then been saved in the drawing? 

[AllenJessup]

A Reference Template would.

From the KN article linked above:

You can use reference templates to manage styles, settings, layers, and other standard drawing components.

You can attach one or more reference templates to an Autodesk Civil 3D drawing so it will be updated on an ongoing basis with changes to the referenced components in the templates.

[!AjI!]

Thanks for that reply, I guess this is what must be happening with my drawings.

There are reference template(s) in use and they must be screwing around and corrupting the 3D extrusions.

Looks like I'll be spending a load of wasted time having to sort this out. (Seems to have happened on at least 14 of the 20 drawings I've produced over the past month).

[AllenJessup]

I'm not sure that's definitely your problem. It's just the only thing I could think of that would change units when you reopen a drawing. I'd also point out that if you use Edit Drawing settings from the ToolSpace. You can't select millimeters as a Drawing Unit.

[!AjI!]

Yeah I had already tried the drawing settings option but instead of the 3D objects sitting at 1000x upscale of millimetre units, they then sit at 1000x upscale of metre units. It seems simply changing that setting doesn't scale down the objects in modelspace. (ie. 1 unit of model space stays as 1 unit of modelspace, even though the drawing now calls it a metre instead of a millimetre).

Any way, as you mentioned it may be a template reference, I looked back at one of the drawings that this issue didn't affect. I've then done a save-as and emptied the drawing of its modelspace items and have CTRL+SHIFT+C from old drawing in to the new empty drawing, and this seems to be a quick work around which will save me a lot of time.

Thought I was going to have to redraw a lot of the items in a new drawing which would have taken me over a week to do.

Thanks again for your help.