How to set cover depth for underground utilities?

[dsun2016]

Hi I'm new to AUD. Just wondering how I can set the cover depth for new underground ducts?

The design surfaces have been created. When I draw underground, the ducts seem to be around 1.5 metres below the surfaces. We'd like to change the cover to 0.6 metres. Can anyone tell me how to do that please?

Thanks.

David

[dave.w · Accepted solution]

The depth of ducts below ground/segment level is defined according to the 3D Model assigned to the Segment model in the Industry Model Configuration. The 3D model defines ports to which the ducts are assigned so each has a unique depth and offset within the trench, relative to the segment line. The vertices of the segment line will have an elevation assigned to match any terrain specified, but the elevations can also be adjusted using AUDTRANSITIONPOINT. The ducts will be offset relative to the segment line's elevation according to the offset defined in the 3D Model for the corresponding port. The Detail assigned to a segment model should match the 3D Model assigned to that model and if the detail block is scaled 1:1, the exact same block can simply be assigned as both the Detail and 3D Model for that segment. The assignment of ducts to ports/locations in the trench will be done automtically, but can also be changed by either: inserting a detail for the segment and moving the duct port blocks OR using the AUDDETAILEDIT command. The process for configuring this is explained more fully in the following whitepaper (available via subscription center): "Detail and 3D Model Creation for Trench and Structures"

[dsun2016]

Thank you very much for your reply Dave. 

The command AUDTRANSITIONPOINT can almost solve my problem, but it is a little bit different from what I expected. We'd like the duct to be, say 0.6 metres strictly from the surface in accordance with the terrain. When I draw a straight duct in AUD, it seems that I can only offset the depth at the start and end insert points. However there should be a lot of points (vertical changes) along the straight line. We hope the line can be draped onto the suface to get the points then they can be offset 0.6 m below the surface continuously throughout the corridor.

Can you tell me is there any way I can do that in AUD please? Or can I create a duct from an object like 3d polyline in AUD?

Thanks.

David

[dave.w · Accepted solution]

Initially only the vertices of the segment (and duct) 2D line will have elevations assigned. To create additional sub-segments for the 3D line you can add transition points using the button on the AUDTRANSITIONPOINT palette or directly with the AUDTRANSITIONADD command. Each transition point will then be draped on the surface with a matching elevation at that point. Note that if a transition point creates enough of an angle between the adjacent line segments due to elevation changes it may trigger creation of vertical sweeps at the transition depending on how sweeps are configured. AUD will not automatically drape along the surface without the transition points being explicitly specified, but this is due to the need for controlling the location of such points due to the impact on angles, sweep creation, length of straight duct, etc. In your case I would recommend defining the Segment 3D Model such that the port for the duct is offset 0.6 meter below the origin/reference point of the segment. That will ensure the duct is always 0.6 meters below 'ground level'. It is expected that the Segment is considered ground level in 3D (although the Segment line is not shown in 3D by default). Once the Segment 3D Model is defined with the duct port offset of 0.6, you should only need to add transition points at each location where you want to drape to the terrain, and the duct vertex in 3D should be located 0.6 meter below the terrain at each of those locations.

[dsun2016]

Thanks Dave. Your reply is great helpful.

One more question about the surfaces. We have several different layer of surfaces at the same place, for example exisitng ground, design ground, design pavement layers etc. When I attach the surfaces file as a xref to the AUD file, how can I define which surface to use for AUD design?

Thanks.

David

[dave.w]

When placing new facilities the elevation will be assigned according to the highest elevation that can be found among all the available surfaces. If you need to use a lower surface you can use the AUDELEVATIONSET command after placement to assign the elevation to a set of selected objects using a specific selected surface. Also, a surface will only be used when visible so disabling its visibility or its style's visibility will allow the surface to be ignored during digitizing and the next higher surface elevation will be used.