StormCAD invert elevations are changing

Hello Damien,

What are the settings for the conduit properties "Set Invert to Start" and "Set Invert to Stop"? If these are set to True and you change the invert elevation on the manhole or catch basin the conduit is connected to, the conduit start and stop invert elevation will change as well. If you do not want to use the same invert elevation for the conduit as the end node, set these fields to False and you will be able to set the invert elevation manually. 

Otherwise, if you are modeling a Design run in StormCAD, the invert elevations can change depending on the design settings. If you run an Analysis calculation, the invert elevations will not change.

If this doesn't help, more details about what data is changing and when it is changing may be needed.

Regards,

Scott

Hi Scott,

Thanks for following up.  I have set design options for structures and pipe inverts to false.  I am trying to run an analysis model as its an existing conditions model. When I type in the surveyed invert (612.27) in the highlighted field below, it automatically changes to 611.44.  I have tried setting "Set Rim to Ground Elevation?" to false as well but that doesn't change the behavior.  I suspect it has something to do with a rule regarding the inlet in the inlet catalog; however, when I reviewed the catalog I could not find a parameter for minimum depth. 

Cheers,
Damien 

The structure is placed as a 3D cell consisting of a 3D Top Cell and a 3D Bottom Cell.  The 3D Top cell has a point in it that represents the top or ground elevation (Construction Class point, Linestyle 5) and there is also a point in the 3D Bottom cell that represents the invert elevation (Construction Class Point, Linestyle 5).  The vertical distance between those two points is the minimum depth that the structure can have.  If you try to move the invert to a shallower depth it will go back to that minimum.  Typically the 3D cells will be created where those two point locations will have a vertical distance of 1 foot or so.  Having a structure of this type less than 1 foot in depth is not very likely so that way users would not run into this very often. 

In this case the minimum or vertical distance between those two point is most likely 2.625 feet.  But to be sure we would need access the 3D cell in the library, find those two points and measure the distance between them.

Here is a link to the help section on this.

https://docs.bentley.com/LiveContent/web/Drainage%20and%20Utilities%20CONNECT%20Edition%20Help-v3/en/GUID-5538CEA4-D3C1-462A-9EC0-978CCE75BCE3.html

Ok, thank you for this explanation.  I'm almost certain this is the issue.  I imagine that this is due to the cells coming from the DOT library and being set to minimum design depths.  So, either I need use a default inlet that uses another cell or copy this predefined cell and link it to a copy of the inlet feature definition?  I really want to keep everything in ORD. 

Hello Damien,
remember that when using ORD, you are creating a 3D model when you place drainage elements.  When you place a node such as an inlet or manhole, ORD creates a 3D model of that node using two cells from your referenced cell library: a top cell and a bottom cell.  It then extrudes either the top or bottom cell (depending on a setting) so that the height of the overall 3D structure matches the difference between the rim and invert elevations.  However, although the cell can be extruded to a depth larger than the cell in the library, it cannot be reduced.  Go to your cell library and check the following:

1. Top cell.  What is the depth of the structure measured from the "rim point" (should be using Linestyle = 5) and the "alignment point" (LS = 3)?

2. Bottom cell.  What is the depth of the structure measured from the  "alignment point" (LS = 3) to the "invert point" (LS = 5)?

The overall node depth cannot be less than the sum of these two depths.  Easiest way to check elevations of these points is to snap on them and review the Z elevation in the message center.

You may need to edit your cells if you want to model nodes that are shallower than your current cells allow.

Hi Karl,  thank you for the reply and information!  I have located the bottom cell in the cell library and found a saved view the shows the bottom of the cell in Top, Front, Right, and 3D views.  I am limited in my knowledge of working with cells in the Bentley ecosystem as I am a recent convert from Civil3D to ORD.  I think I might need to "break" the cell b/c when I click on it it is called a smart solid and when I select the points that represent the top and bottom of the inside of the bottom of the inlet I cannot change any of the x,y,z values. 

I am looking for resources to help me understand how to move the bottom of the structure up to 1'.  I can change the Z-values of the point in the bottom of the cell (see below); however, I hoped that the entire structure bottom would shift up by the same amount (that didn't happen). 

The cell is a "smart solid" and I'm not sure how or if I need to "break" it in order to edit the faces/vertices up ~1' (see below).

Any assistance pointing me in the right direction would be greatly appreciated!  Cheers!

I have read/watched the following trying to understand how to edit the depth of the cell but have not yet figured it out:

Hi Damien,

Do not try to break or drop the solids. They need to be edited using the solids editing tools. I suggest doing the 3D modeling tutorials on the Bentley Learn Server. Also, review the requirements for SUDA cells in the software documentation so that you understand what the requirements are - refer to the link in Beebe’s post.

If you are new to ORD, you may want to reach out to the DOT person who did the cell library and configuration. This is an easy change for someone who already has the solids modeling skills. 

Hi Damien,

Do not try to break or drop the solids. They need to be edited using the solids editing tools. I suggest doing the 3D modeling tutorials on the Bentley Learn Server. Also, review the requirements for SUDA cells in the software documentation so that you understand what the requirements are - refer to the link in Beebe’s post.

If you are new to ORD, you may want to reach out to the DOT person who did the cell library and configuration. This is an easy change for someone who already has the solids modeling skills. 

Hi Karl,

Thanks for the point in the right direction! I knew there had to be a proper way to modify these.  

Cheers,
Damien