Model translucency issue in 1.7

[pjcozzi]

@bagnell I will send you the model. Can you look at this? Perhaps this is an OIT change? However, setting orderIndependentTranslucency to false did not help. I tried to briefly tweak the model alpha values, but it also did not help.

1.6:

1.7:

[bagnell]

@pjcozzi Does the model create separate commands for back/front faces when blending is enabled? The commands being submitted were only those culling the back faces. If you turn OIT off, this model still doesn't look right.

[pjcozzi]

Does the model create separate commands for back/front faces when blending is enabled?

No. We could do this, but I think I would want to do it server-side so that the Cesium client truly renders what the model describes, not what we think it should describe.