Volume Surface Boundaries

[beccasme]

Hello,
I am working in Civil 3D 2012. I created a grid volume surface based on two other surfaces I have in my drawing. One of the surfaces is extremely large and re-building the volume surface takes an extremely long time, i'm assuming because it's calculating every point of the large surface, even though my comparison surface only covers a fraction of it. I want to add a boundary to the surface so it doesn't have to go through the entire large surface, however when I add an outer boundary to the volume surface, all of the information disappears, as if it excludes the information. When use the same boundary but make it a "show" boundary it works, however it's still going through and calculating all the points on the large surface.

I don't want to do a bounded volume under the analysis tab because I need an acutal surface to work with and apply styles to for further design. Applying a boundy to my comparison surface didn't do it, and I can't add the boundary to the large surface because I need it to compare other surfaces i will create in different areas (also it's only a data reference in this drawing.)

Does anyone know why the "outer" boundary isn't working? (i'm using a simple polyline for the boundary) Does it need a special sort of object for volume boundaries?

Any help?! thanks!!

[tntdraftsol]

I don't know if adding an outer boundary to the Volume surface is the way to go. You might try creating a new surface and pasting in the large surface (essentially you are making a copy of the large surface).

After you have the new surface with the large surface you spoke of pasted in add the outer boundary you want from the polyline you had created. You should now have a surface you could create a new volume surface with to get your comparison. I would think by doing this you would cut down on the calculation time, but I am not for sure on that. Granted you would need to make mutiple "copies" of the larger surface and add outer boundaries where needed for your other sites for comparison.

Hope this helped.

[sinc]

Seems like in a demo, I saw something about a way to "clip" a Surface reference, so that you were only looking at a small area of a very large Surface. This made it possible to work in a small area of an extremely large Surface without slowdowns. I think the "large" Surface might need to be in a separate drawing, then you can DREF in just the area you're interested in.

I can't find anything about it in the Help, though... :(

[brian.hailey933139]

Sinc,

I believe you are talking about a cropped surface. Basically it creates a new surface in a new drawing based on an existing surface. This is not a data reference because you can edit this new surface as needed and you can set it up so if the old surface changes, the new surfaces changes as well.