4270868f56bd1211af09">LayerProperties</a>() : surface_area(0), weight(0) </div><div class="line"><a name="l00192"></a><span class="lineno">  192</span>&#160;        {}</div><div class="line"><a name="l00193"></a><span class="lineno">  193</span>&#160;};</div><div class="line"><a name="l00194"></a><span class="lineno">  194</span>&#160;</div><div class="line"><a name="l00196"></a><span class="lineno">  196</span>&#160;</div><div class="line"><a name="l00199"></a><span class="lineno"><a class="line" href="str