WebGLRenderer: Removed opacity === 0 checks. Fixes #1750.

src/renderers/WebGLRenderer.js

@@ -2886,8 +2886,6 @@ THREE.WebGLRenderer = function ( parameters ) {
 
 	this.renderBufferDirect = function ( camera, lights, fog, material, geometryGroup, object ) {
 
-		if ( material.opacity === 0 ) return;
-
 		var program, attributes, linewidth, primitives, a, attribute;
 
 		program = setProgram( camera, lights, fog, material, object );
@@ -2978,8 +2976,6 @@ THREE.WebGLRenderer = function ( parameters ) {
 
 	this.renderBuffer = function ( camera, lights, fog, material, geometryGroup, object ) {
 
-		if ( material.opacity === 0 ) return;
-
 		var program, attributes, linewidth, primitives, a, attribute, i, il;
 
 		program = setProgram( camera, lights, fog, material, object );