@Override
    public boolean renderWorldBlock(IBlockAccess world, int x, int y, int z, Block block, int modelId, RenderBlocks renderer) {
        Tessellator tessellator = Tessellator.instance;
        IIcon icon = block.getIcon(0, 0);
        tessellator.addTranslation(x + 0.5F, y + 0.5F, z + 0.5F);

        for (GroupObject groupObject : model.groupObjects) {
            for (Face face : groupObject.faces) {
                int brightness = block.getMixedBrightnessForBlock(world, x + (int)face.faceNormal.x, y + (int)face.faceNormal.y, z + (int)face.faceNormal.z);
                tessellator.setBrightness(brightness);
                tessellator.setColorOpaque_F(1F, 1F, 1F);
                if (face.faceNormal.y < -0.5) tessellator.setColorOpaque_F(0.5F, 0.5F, 0.5F);
                if (Math.abs(face.faceNormal.z) > 0.5) tessellator.setColorOpaque_F(0.8F, 0.8F, 0.8F);
                if (Math.abs(face.faceNormal.x) > 0.5) tessellator.setColorOpaque_F(0.6F, 0.6F, 0.6F);
                for (int i = 0; i < face.vertices.length; ++i) {
                    tessellator.addVertexWithUV(face.vertices[i].x, face.vertices[i].y, face.vertices[i].z,
                            icon.getInterpolatedU(face.textureCoordinates[i].u * 16),
                            icon.getInterpolatedV(face.textureCoordinates[i].v * 16));
                }
            }
        }
        tessellator.addTranslation(-x - 0.5F, -y - 0.5F, -z - 0.5F);
        return true;
    }