Hello, I have troubles with opening some of the .dxf and .dwg files. I use Cad Lib 4.0 and OpenGLExtendedViewExampleCS. When I try to open these files, OpenGLExtendedViewExampleCS always shows black screen. I figured out that GLGraphics3D.CreateDrawables() throws the following exception: [System.ArgumentOutOfRangeException] Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index at System.Collections.Generic.List`1.get_Item(Int32 index) at WW.Cad.Drawing.OpenGL.GLGraphics3D.‰.‰(IList`1 polylineA, IList`1 polylineB, Boolean closed) at WW.Cad.Drawing.OpenGL.GLGraphics3D.‰.‰(Polyline2D polylineA, Polyline2D polylineB, Boolean fill) at WW.Cad.Drawing.OpenGL.GLGraphics3D.‰.Visit(Polyline2D2WN visitee)jr at WW.Cad.Drawing.Surface.Polyline2D2WN.Accept(IPrimitiveVisitor visitor) at WW.Cad.Drawing.OpenGL.GLGraphics3D.Ÿˆ.Draw(›ˆ converter) at WW.Cad.Drawing.OpenGL.GLGraphics3D.‰.œˆ(›ˆ converter) at WW.Cad.Drawing.OpenGL.GLGraphics3D.CreateDrawables(ProcessedGraphicElementBlock graphicElementBlock) at OpenGLExample.GLUtil.InitGLGraphics(GLGraphics3D glGraphics, DxfModel model, Bounds3D bounds, Size2D targetSize) in C:\Users\denis.maslou\Documents\CadLib 4.0\Examples\OpenGLExtendedViewExampleCS\GLUtil.cs:line 86 I have also checked that the WinFormsExtendedViewExampleCS can open these files. Here you can download the problem dxf file. I'm looking forward to hearing from you. Thanks, Denis.