can not close corner

Hi All,

there are a couple of things about these corners:

1. Why is the corner so big?  Because we have to open the bend area so that bends do not interfere.  Basically we cannot mimic deformed corners by default since the unfold algorithm would not know how to handle intersecting portions of the corner (one of teh basic sheet metal rules:  there may not be intersecting bend areas!  since basically we are using the flat portions of a sheet metal body, calculate the developed length of the adjoining bend, stack the developed length of the bend to the flat portion and then add the next flat portion to the bend and so on...).  Bottom line we cannot handle intersecting bend areas since the flat pattern would not be obvious to calculate.
2. Is there a way to get around this limitation?  Partially.  With 2016 we have introduced "three bend corner reliefs" and with 2017 we added some missing enhancements (like cutouts smaller than the required relief).  Since we allow the creation of closed corners with the three bend corner relief we know which geometry was added by this feature and in order to flatten the part we can temporarilly remove the additional material, flatten the sheet metal body and then add the temporarily removed material to the flat pattern again.  However depending on the complexity of the geometry we cannot always add the expected corner treatment since we would create topological incorrect bodies and the three bend corner feature might fail.  So not sure if you get exactly the result you would want to achieve.  All of the corner treatments work best for 90 degree bends (obviously) and we can add smaller cutouts or no cutouts at all to those corners:
   
   In this case we can create a full round corner (top picture) or a suitcase corner with relief:
   
   And we can create the flat pattern of it:
   
   Notice that you have to turn off "Show Slit" in order to get the optimized (geometry added to the flat) flat pattern:
   Otherwise you will see the default flat pattern.
3. Why did you not stumble over this feature by yourself?  As mentioned above we did introduce 3D corner reliefs, especially the three bend corner reliefs with 2016/2017 and if you are using a SOLIDWORKS version before 2016 you obviously won't get this feature.  Looking at the original file I noticed that the file was either created before SOLIDWORKS 2013 or the template which was used to build this part was created before SWX 2013.  Before 2013 we created sheet metal features for multi body parts on the fly, at any postion in the tree, all over the place and as it sounds this could become very confusing.  Before the first sheet metal feature of the sheet metal body we inserted the sheet metal defintion in order to hold the sheet metal defintion.  So every new sheet metal body would add another sheet metal feature and it was hard to predict which feature controls which body, respectively the other way round, how can I locate the sheet metal feature that controls this particular body?
   
   With 2013 we have changed the multi body sheet metal architecture and we have a global sheet metal defintion and body specific sheet metal defintions always at the top of the Feature Tree:
   
   Since then we have developed quite some sheet metal features (i.e. Corner Reliefs) and mostly all of the new sheet metal features do not support the old architecture.  Therefore we do not show the new features when we detect a part with the old sheet metal architecture.  So therefore you migh be missing the Corner Relief feature:
   

Perhaps this helps to understand why we have to use these big corner reliefs, how you can get around them and why you are perhaps mssing the Corner Relief feature even though you are using i.e. 2018.

Kind regards

Frank

SOLIDWORKS Product Defintion Team