Display Mode 2

I bring this up again. I spend now many hours try to fix this. it becomes a real problem now.

let me explain again:

ais_shape, showing a BRepPrimAPI_MakeBox... and with displaymode (dm) 1: 
when I change the dimensions of the shap and redisplay all is correct displayed. I can go larder and smaller no problem at all, in all display modes BUT 2

if I switch ONCE to display mode 2, and i increasy the size, all is good. but I can go smaller anymore then the size i had when switching to dm 2. 

it is like in dm2 it only updates when it is increasing but not decreasing. This must be a bug.

I tried everything:

//m_occView->context()->Erase(m_aisMain, Standard_False);
//m_occView->context()->Display(m_aisMain, Standard_True);
//m_occView->context()->Redisplay(m_aisMain, Standard_True);

m_aisMain->UnsetAttributes(); // Clears cached visual attributes
m_aisMain->SetToUpdate(); // Marks the shape as needing a full update
m_occView->context()->Redisplay(m_aisMain,       true, true);

m_occView->getView()->Invalidate(); // Marks everything as needing a redraw
m_occView->getView()->Update();

m_occView->context()->UpdateCurrentViewer();

nothing works

I so need help here.

Thanks!

Bnd_Box bbox = m_aisDisplay->BoundingBox(); // Get the bounding box

bbox is only accurate updated if it gets bigger

BRepBndLib::AddOptimal(m_aisDisplay->Shape(), bbox);

this always works correct

m_aisDisplay->BoundingBox().CornerMax().SetXYZ(bbox.CornerMax().XYZ());
m_aisDisplay->BoundingBox().CornerMin().SetXYZ(bbox.CornerMin().XYZ());

was hoping i can overwrite but this doesn't work

now I am out of ideas

AIS_Shape::Compute() for display mode 2 displays bounding box of a shape returned by AIS_Shape::BoundingBox().

If you'll take a look at AIS_Shape::BoundingBox() implementation, you'll see that bounding box is cached in myBB and updated only when flag myCompBB is changed:

  if(myCompBB) {
    BRepBndLib::Add (myshape, myBB, false);
    myCompBB = Standard_False;
  }

and the only place where this flag is changed is AIS_Shape::SetShape():

  void SetShape (const TopoDS_Shape& theShape)
  {
    myshape  = theShape;
    myCompBB = Standard_True;
  }

Neither of the methods resets bounding box (myBB.SetVoid() or similar), hence it is only expanded, which is indeed a bug. You may file a bugfix to OCCT or workaround bug by clearing myBB on your own or implementing ::Compute() at application level.

Anyway, if you really want to display box around the shape, then overriding ::Compute() and displaying oriented bounding box BRepBndLib::AddOBB() instead of AABB might look better to user.

Thank you!

Not sure if I have to do something now. Report that bug? Could you do this and I just wait until it is fixed?

Visualization - Bounding box is not decreasing for mode 2

PR: Visualization - AIS_Shape bounding box re-computation is not working properly

During today I will prepare the fix (at the moment writing a tests)

great news - thanks!

Test case:

pload MODELING VISUALIZATION
box b 100 200 300
vinit View1
vdisplay b -dispMode 2
# OK
box b 10 200 300
vdisplay b -dispMode 2
# KO - bounding box is not shrunk

Possible fix:

Subject: [PATCH] Visualization, AIS_Shape::BoundingBox() - reset bounding box
 before adding a shape to it

---
 src/AIS/AIS_Shape.cxx | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/AIS/AIS_Shape.cxx b/src/AIS/AIS_Shape.cxx
index eb9e7f68e7..ceb4d863dd 100644
--- a/src/AIS/AIS_Shape.cxx
+++ b/src/AIS/AIS_Shape.cxx
@@ -792,7 +792,9 @@ const Bnd_Box& AIS_Shape::BoundingBox()
     return myBB;
   }

-  if(myCompBB) {
+  if (myCompBB)
+  {
+    myBB.SetVoid();
     BRepBndLib::Add (myshape, myBB, false);
     myCompBB = Standard_False;
   }
--