Test cases:

NO PROTEIN, NO NUCLEIC
1hpn 1HPN (neither protein nor nucleic): Should refuse since icn3d does nothing.

BB ONLY
1qo1 1QO1 protein CAO.
1qzb 1QZB RNA P only.
1bdx 1BDX protein and DNA, bb atoms only.

MIXTURES, SOME BB ONLY, SOME MORE
1mj1 1MJ1
486d 486C

SOME WHITE CHAINS IN ICN3D
4aoj 4AOJ 26K in BU1, 6K in AU, surface produced with some white regions.
3ra0 3RA0 BU=6K, AU=1.5K, RNA has plain red/white chains.

HUGE ASSEMBLIES THAT WORK IN ICN3D
4ioa 4IOA BU=AU=84K protein 24K atoms works! (RNA 60K fails)
5sze 5SZE nice BU > AU. Clean result.
1SVA! BU=959K, AU=16K.

iCn3D SAYS TOO MANY NON-H ATOMS (">30,000")
6cri 6CRI 53K in both BU & AU (simplified or not, makes no difference to iCn3D!)
1hqk 1HQK BU=80K, AU=7K.
6HKT 6hkt BU=AU=82K.
4ioa 4IOA BU=AU=84K protein 24K atoms works! (RNA 60K fails)