Calculated Wrong Volumes

Hi, I'm working in Land Desktop 2009 and my calculated cut and fill volumes are wrong. I'm working on a dredge project and need to calculate cut volumes to restore a ditch with 3:1 side slopes. I built my ditch with 3D polylines and matched every step in the tutorial and my volumes are way off. Help.

No experience with LDD here but if you'll pardon me for asking how far off were you? Was the ditch you refer to constructed full size or to a particular scale?

the ditch is built to scale and I'm off by a factor of 30! I think i just found part of the problem. My volume surface shows a maximum elevation of 14 and min of -3 my elevations range from 0 to -12. I think i need to change my range.

Sounds like a possibility. In the meantime perhaps someone with LDD experience will come across your post and confirm/deny your assumption or provide a solution or plausible explanation at least. We'll just give this thread a "bump" to get it back in view. Here goes da bump.......

You don't say what units you are working in, but if you think you are working in metres, perhaps LDD is working in feet, and the volume is being divided by 27 to give the result in cubic yards.

I have this problem with LDD 2005. Even though the prototype drawing is set to default in metres, all the volumes were out by a multiplication factor of 27. So what I do now is to open the drawing and set up a new project, then from the top menu I go to Projects - Drawing Setup - Units. I then click on the Feet in Linear Units, and then click on the Metres. This seems to convince LDD that I really want to work in metres.

It got to the stage that I was making a test volume which had a bottom surface that was a rectangle of 100 metres square, and a top surface 10 metres higher. I then did the volume for these two surfaces and if the answer was 100000, I knew it was working in the correct units

I don't know how LDD 2009 behaves, but it is an aspect you could have a look at.

Thanks eldon for jumping in here. I was definitely out of my element.

Thanks for the help. I was working in feet and did not expect LDD to calculate yards for me. I changed to meters and found my cubic foot number to make sure LDD was in fact converting to yards.

I tried the two rectangles check and could not get LDD to recognize the whole rectangle. Could you please provide more detail on how you did this?

I drew a rectangle of 100 by 100. I then copied this to a place 10m higher on the same X,Y coordinates. Then I took a front view, and set each rectangle to its own layer. Then back to a top view and created two surfaces by freezing the other layer each time when you came to pick the layer of the 3d lines.

Something like that I think. It is so long since I found out how to convince LDD of my units, that I don't bother now with the test