Mistake in Figure 8.10.3.9.A

[VDobranov]

Hello!

The Figure 8.10.3.9.A (https://github.com/buildingSMART/IFC4.3.x-development/blob/master/docs/figures/ifcmateriallayerwithoffsets_fig-1.png) shows that IfcMaterialLayerSet for IfcWallType is composed of:

• IfcMaterialLayerSetWithOffset which doesn’t exist in specs;
• IfcMaterialLayerSet which violates 8.10.3.7.5 Formal representation:
  

I suppose these parts should be as follows:

• IfcMaterialLayerWithOffset
• IfcMaterialLayer
  

[aothms]

@VDobranov I think you're right. @TLiebich, do you still have the originals for this? Otherwise I think we can go ahead with the corrections as you made them simply drawing over the existing image. A pull request for this (without the red ellipse) would be appreciated :)

[TLiebich]

Hi, I found the original figure and improved it. I did two more modifications:

1. replaced IfcWallStandardCase with IfcWall (due to deprecation of the first)
2. in the lower left figure, the axis was wrongly named - it should be "y" instead of "x" - the material layers are defined along the Axis2 (i.e. y-axis).

In addition, the definition of the two additional attributes got lost in the transition to IFC4.3. Here the original definitions from IFC4:
OffsetDirection: Orientation of the offset; shall be perpendicular to the parent layer set direction.
OffsetValues: The numerical value of layer offset, in the direction of the axis assigned by the attribute OffsetDirection. The OffsetValues[1] identifies the offset from the lower position along the axis direction (normally the start of the standard extrusion), the OffsetValues[2] identifies the offset from the upper position along the axis direction (normally the end of the standard extrusion).