Jeremy, one of Tocic's VDC Modelers brought this to my attention this morning. We played with it for a little bit, but couldn't figure it out. I obviously forwarded the issue to Autodesk, but figured I should share with all of you - in the event that we are missing something simple (or there is a less than simple fix!).
The Goal: Slope pipe: 1/4" every 10'
Usually to slope, we just select the entire area that needs to slope and type the required slope. Works like a charm - locating each fitting and pipe at the correct elevation. We did the same thing in this case, but apparently, it is too small of a slope for Revit. Geometry didn't change; slope on pipe reads 0"/12".
No, this slope isn't huge, but the main runs 200', which is a change in elevation of 5". That clearly will affect coordination.
We found a workaround, but it isn't realistic to do this on the entire system, so we've decided just to do it on the main (which has about 5 bends in X/Y). If you change the elevation of one end of the pipe to the manually calculated value, it will slope it (although the elevation still reads 0"/12"). So for each bend on the main, we have to calculate the elevation based on the slope and manually type. (I hope the layout doesn't change too much!) We have decided to ignore the slope on branch lines for now, which run about 50' - only because we don't have to have to do so much work if things change.
This really shouldn't be a problem. Are we missing something or can Revit really not recognize slopes below a certain amount? Is there a better workaround?