boolean voxelIsInTrough(float dVS, float rAS2, float rBS, float dAB, float dAV, float dBV) {
		// only calculate what we need -- a factor proportional to cos
		float cosASBf = (rAS2 + rBS * rBS - dAB * dAB) / rBS; // /2 /rAS);
		float cosASVf = (rAS2 + dVS * dVS - dAV * dAV) / dVS; // /2 /rAS);
		return (cosASBf < cosASVf);
	}