Possible reasons for "WARNING: incorrect port slice (Cut Intake Port Body 1)"

The following list gives possible reasons for warning "WARNING: incorrect port slice (Cut Intake Port Body 1)" when executing Create Cylinder and Valves:

1. Valve Face naming not according to the User Guide. 
   Wrong naming could lead to a wrong placement for the valve curtain interface.
   Especially naming of valve margin is important for valves with relative "thick" margin.
   
   
2. Highly tolerant edges and/or vertices with a tolerance higher than 5e-5 m (see Simcenter STAR-CCM+ - User Guide (html) (siemens.com) - Home>Add-ons>Simcenter STAR-CCM+ In-cylinder Solution>Geometry Requirements )
   
   close to the valve curtain interface and/or the valve stem-port intersection.
   Those edges/vertices could cause a failure of a Boolean Subtract of the valve body from the engine body.
   
   
3. Edges at the valve stem-port port intersection.
   Also those edges could cause a failure of a Boolean Subtract of the valve body from the engine body

Note that this list is only a summary of reasons which were clearly identified as causing this warning but might not be exhaustive.

Warning/Error Reproduction

With the following and the corresponding video we will walk you step by step for identifying all problems from above for a geometry that shows the following warning and error messages when running Create Cylinder and Valves for a full model:

WARNING: incorrect port slice (Cut Intake Port Body 1)
         adjust "Normalized Valve Curtain Interface Position"
         via "Engine > Intake Valve N > Edit
WARNING: incorrect port slice (Cut Exhaust Port Body 1)
         adjust "Normalized Valve Curtain Interface Position"
         via "Engine > Exhaust Valve N > Edit
Tessellating part Valve using distance-biased density.
Tessellating part Port Volume Control using distance-biased density.
Tessellating part Valve Head Volume Control using distance-biased density.
Tessellating part Valve Port Volume Control using distance-biased density.
Tessellating part Valve Curtain Interface Volume Control using distance-biased density.
Tessellating part Valve using distance-biased density.
Tessellating part Port Volume Control using distance-biased density.
Tessellating part Valve Head Volume Control using distance-biased density.
Tessellating part Valve Port Volume Control using distance-biased density.
Tessellating part Valve Curtain Interface Volume Control using distance-biased density.
Tessellating part Valve using distance-biased density.
Tessellating part Port Volume Control using distance-biased density.
Tessellating part Valve Head Volume Control using distance-biased density.
Tessellating part Valve Port Volume Control using distance-biased density.
Tessellating part Valve Curtain Interface Volume Control using distance-biased density.
Tessellating part Valve using distance-biased density.
Tessellating part Port Volume Control using distance-biased density.
Tessellating part Valve Head Volume Control using distance-biased density.
Tessellating part Valve Port Volume Control using distance-biased density.
Tessellating part Valve Curtain Interface Volume Control using distance-biased density.
WARNING: incorrect port slice (Cut Intake Port Body 1)
         adjust "Normalized Valve Curtain Interface Position"
         via "Engine > Intake Valve N > Edit
WARNING: incorrect port slice (Cut Exhaust Port Body 1)
         adjust "Normalized Valve Curtain Interface Position"
         via "Engine > Exhaust Valve N > Edit
WARNING: incorrect port slice (Cut Intake Port Body 1)
         adjust "Normalized Valve Curtain Interface Position"
         via "Engine > Intake Valve N > Edit
WARNING: incorrect port slice (Cut Exhaust Port Body 1)
         adjust "Normalized Valve Curtain Interface Position"
         via "Engine > Exhaust Valve N > Edit
**ERROR (Cylinder): Valve subtract feature failed.
**ERROR (Cylinder): Intake port creation feature failed.
**ERROR (Cylinder): Exhaust port creation feature failed.

First we will reproduce the warning and error messages with these steps:

1. Create a new simulation
2. Open In-cylinder
3. Import geometry using attached file In-Cylinder_GasolineEngineTraining_Geometry_IncorrectPortSlice.x_b
4. Right-click the Engine node in the In-Cylinder simulation tree and select Create Cylinders and Valves.
   This will fail as shown below.
   

Problem Identification

Now we can check if the valve curtain interface is correctly placed by continuing from step 4.

5. Right-click Geometry and select Edit 3D-CAD.
6. Right-click In-cylinder 3D-CAD 1, selected Edit Display Resolution. Choose Very Fine.
7. Tick on display of All Edges.
8. Right-click feature Cylinder Feature 1 and select Roll Back.
9. Select bodies engine-fluid, Exhaust Valve 1: Valve, Exhaust Valve 2: Valve, Intake Valve 1: Valve, Intake Valve 2: Valve  and all sheet bodies while having the Ctrl key pressed.
10. Use Display Cut Bodies Using Multiple Planes in the XZ-Plane and with Show Cap ticked off. 
    Move the plane to multiple Y locations to identify if the sheet bodies which correspond the valve curtain interfaces clearly intersect the valve faces and their corresponding port.
    For this example all sheet bodies are at the correct location although for all valves their margins were not named.
    Nevertheless, later we will name the margin of all valves.
    

Now we can check if there are highly tolerant edges/vertices by continuing from step 10.

11. Click on Show Filter.
12. Set Selection Mode to Selected Entities.
13. Select body engine-fluid.
14. Set Input Type to Edges.
15. At Conditions select Tolerance and set a value of 5e-5 m.
16. Click on Search.
    There are 2 highly tolerant edges corresponding to the port seat which need to be corrected.
    

Now we can check if the are edges at valve-port intersection by continuing from step 16.

17. For all valve bodies and the engine-fluid body there are edges right at the valve-port intersection as shown with the highlighted edges below.
    
    
    
    

Corrections

From the problem identification we know that these corrections are necessary

• margins of all valves need to be named
• 2 highly tolerant edges removed 
• edges at valve-port intersection removed

which we will do using the following procedure:

1. Create new simulation
2. Click on Import CAD Model into 3D-CAD and select attached file In-Cylinder_GasolineEngineTraining_Geometry_IncorrectPortSlice.x_b
3. Right-click In-cylinder 3D-CAD 1, selected Edit Display Resolution. Choose Very Fine
4. Tick on display of All Edges.
5. One by one select all CAD faces of a valves margin and name them accordingly
6. Offset the upper port seat edge by 1 mm
   
7. Delete the port seat faces next to the tolerant edges
   
   This is necessary because otherwise Optimize Edges at step 6. cannot sufficiently reduce the tolerance of the edges.
8. Optimize the highly tolerant edges
   
9. Merge the former highly tolerant edges
   
10. Extend the port seat face by 0.5 mm
    
11. Sew the sheet body with tolerance 1e-6 m
    
12. Select all edges at the valve-stem port intersection and remove them using Repair Tools>Remove Redundant Edges.
    
    
    
13. Export the geometry