importing logic introduced lots of drc errors related to max/min neck length

Yep, I see it.  The problem is on pg 21 of the design.  (Looks like you guys are using a non-Cadence front end such as Mentor DxDesigner for schematic?  Yuck.)  See if you can find the problem over by U186 and C1503.  If you get stuck write back and I'll give a bigger hint.

i noticed that, corrected it.

the netlist created from schematics is ok i believe, i have compared this with the one exported from pcb file.

obviously this netlist has nothing to do with neck width/length. but somehow, after import, lots of drc errors emerged.

does not make sense to me.

btw, the number of errors, changes from time to time.

i noticed that, corrected it.

the netlist created from schematics is ok i believe, i have compared this with the one exported from pcb file.

obviously this netlist has nothing to do with neck width/length. but somehow, after import, lots of drc errors emerged.

does not make sense to me.

btw, the number of errors, changes from time to time.

There are more than 800 hidden DRCs in the original board.  When you import a new netlist, many of the conditions that were waived get re-checked and re-appear.  It's best to un-waive all the DRCs first unless you feel you have a good grasp on what's going on.  The design uses a number of "bad" practices which will result in a huge number of shorts appearing in the IPC net check unless someone is managing an exception list (really bad!).  

So when I start your board and un-waive all the existing DRCs then the netlist import (with the correction I mention above) does not generate any *new* DRCs.  However, when I bring in the waived DRC board (from your original zip) and then import the netlist I get around 165 "new" DRCs but they are appearing since they got flagged as changed during import - but it is the same error as existed before.  The new netlist has renamed a significant number of nets from a simple alpha-numeric name to  a "$"+alphanumeric.  This is what is triggering the re-check of the DRC.

well, after remove $ from netname, drc report is here:

https://github.com/chaujohnthan/zcu104hardware/blob/master/consmgr1.rpt

after restore all of the waived drc error:

https://github.com/chaujohnthan/zcu104hardware/blob/master/consmgr.rpt

without remove $ sign, import logic directly:

https://github.com/chaujohnthan/zcu104hardware/blob/master/consmgr0.rpt

I think it's how you are importing the new netlist.  If I use File->Import->Logic and set my option "Place Changed component = Always" then I get a handful of errors but not the ones you see.  If I set my option to "Place Changed component = Never" then I see thousands of errors including the ones you are seeing.

How are you importing the new schematic?

Place Changed component = Always

tick all the 4 radio box. 

the number of DRC decreased significantly indeed.