City Engine Object Transparency

Question

Hello all,

I'm having a hard time setting the transparency of my models.  I have found the material.opacity cga rule.  This just makes my textures transparent.  I would like to set the texture and the model that is being textured to some level of transparency.

Thanks for any help

MatthiasBuehler1 · Answer

Hi,

This is currently not possible, no. This is a current limitation of CGA.

1] I'd align the terrain to shapes - you may have seen how that works in a tutorial
2] Since a shape can only sample once per model, each subshape during model generation can not sample the DEM again, thus you also can not subdivide the shape or add more points to then drape the shape on the DEM better.
3] The only thing you can do is do it in 2 steps:
   a] use one CGA rule that cuts your shape into smaller pieces *
   b] when this model is generated, select it, right-mouse-click > convert Models to Shapes
   c] use the alignShapesToTerrain tool to align those shapes to the DEM
   d] use your rule to make the transparent models.

* e.g.:attr mySize= 3

@StartRule
Lot -->
    alignScopeToAxes(y)
    split(x) {~mySize: split(z) {~mySize: SmallerShapes. }* }*

ok ?

Tom-PierreFrappé-Sénéclauze · Answer

OK thanks, got it. Need to hide the shapes ("show/hide shapes") button. Then I can see the models, in all their glorious transparency.

For reference, this is the code I used:@StartRuleShape--> 
 set(material.opacity,.02 )
 comp(f) { all = Face }
 comp(e) { all = Edges }

Face-->
set(material.opacity,0 )
 color("#0000ff")

Edges --> 
 comp(e) { all : i("builtin:cube")  s('1, 8, 8) X }

X--> 
set(material.opacity,1)
color("#FFFF00")

Now, as is often the case in 3D, I get issues with some of the lines disappearing under the landscape. Is there a way to add vertices in the lines and re-allign those to the DEM so that the perimeter of the model, at least, follows the DEM?

And similarly, if I was to do the same thing but want to have the entire face, not just the outline, follow the topograhy, is there a way to breakdown the shape (or the model) into smaller shapes so that it can drape better over the topography?

thanks for your thoughts!
Tom

MatthiasBuehler1 · Answer

hi,

Shapes can not be transparent. Only Models can be transparent.

Shape + rule -> Generate -> Model.

So if you still see grey, then you still see the shape. Hide the visibility of shapes via the F11 key or the according button in the toolbar.

ok ?

matt