Reducing quality of Graphics3D scene to improve performance?

Question

ProteinData["SERPINA1", "MoleculePlot"] gives the detailed Graphics3D plot below. I'd like to make many small copies of this object and place them in a single Graphics3D scene, but I'm running into performance problems because the molecule graphics-object is a pretty complicated mesh.

Are there general methods of reducing the quality/detail of graphics objects like the one below that would allow me to place many of these in a single scene?

Answer 1

This plot is very complex one, as each from ProteinData. If you want to loose some weight I can help with the following tricks.

But even with this I don't think you will be able to put large number of the elements with in one plot.

plot = ProteinData["SERPINA1", "MoleculePlot"];

In order to have an idea how the structure of this data looks you can use this:

(plot // First) /. List[(_?NumericQ) ..] :> Sequence[]

No we know what we can get rid of:

reduced = First @ plot /. {Specularity[___] :> Sequence[], 
                           (VertexNormals -> _) :> Sequence[], 
                           (VertexColors -> _) :> Sequence[], 
                           EdgeForm[__] :> Sequence[], 
                           RGBColor[_, _, _] :> Sequence[], 
                           AbsoluteThickness[_] :> Sequence[]};

To improve performance with 3D plots which include duplicate objects the best way is to use GeometricTransoformation + TranslationTransform(for example). It is described well in this fenomenal training by Yu-Sung Chang around 28th minute mark.

Graphics3D[{GeometricTransformation[reduced, 
            Flatten[Table[TranslationTransform[10000. {i, j, k}], 
                          {i, 2}, {j, 2}, {k, 2}]]]}
           , Lighting -> None]

I was able to rotate this quite smoothly with an old pc with on board graphics card!

To go even further I tried to delete half of elements in the molecule, maybe it is not what you need but maybe you can use it:

i = 1;
new = reduced /. x : GraphicsComplex[___] :> (++i; If[OddQ@i, x, Sequence[]])

Graphics3D[{GeometricTransformation[new, 
            Flatten[Table[TranslationTransform[10000. {i, j, k}],
                          {i, 3}, {j, 3}, {k, 3}]]]
           }, Lighting -> None]

27 elements and I'm able to rotate it easily while for this many copies it is not so obvious that they are reduced by half.

Answer 2

Never used ProteinData, but can you try this and see if it speeds thing a little?

g = ProteinData["SERPINA1", "MoleculePlot"];
Block[{$PerformanceGoal = "Speed"}, g]

For me, it seems the plot was a little faster to move around with the mouse with this vs. "Quality" (but you can try it yourself and see). If this seems faster, then you can put all the graphics in that Block to that this option affects all rendering inside.