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      <div class="title_topic3" id="xps10_pagetitle">Layer processing</div>
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               <p class="para_td"><a class="links" href="javascript:void(0)" onclick="top.openFile('dataexchange/dxfdwg_settings.html');return(false);">Overview</a></p>
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               <p class="para_td">How To</p>
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               <p class="para_td"><a class="links" href="javascript:void(0)" onclick="top.openFile('dataexchange/map_spec_proc.html');return(false);">Options</a></p>
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      </table><br><p class="para_topic">DXF/DWG layer names are character strings and could be unlimited in number. &nbsp;Since NX only supports 256 numeric layers, you can use the following processes to map DXF/DWG layers to NX. This processing approach ensures maximum retention of DXF/DWG layer naming when data iterates through multiple DXF/DWG&rarr;NX exchanges.</p>
      <div class="title_division">Import Layer Processing</div>
      <p class="para_division">If the DXF/DWG name for any layer represents a number and is in the range (1&ndash;256), then it maps to the corresponding numbered layer in NX.&nbsp;For example, 1 in DXF gets mapped to NX layer 1, however DXF/DWG Layer one is NOT (automatically) mapped to NX layer 1.&nbsp;Also, a NX category with the DXF/DWG category creates for each DXF/DWG layer. However NX categories are limited to 30 characters.</p>
      <p class="para_division">For all other layers with names that do not represent a number in the range 1&ndash;256, then one of two actions are taken.</p>
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            <p class="para_item">Total number of layers in DXF/DWG file is less than 256.</p>
            <p class="para_item">In this case, we can establish a unique mapping for each DXF/DWG layer to one of the NX numbered layers. All DXF/DWG layers that represent numbered NX layers map first. Then, for each of the remaining DXF/DWG layers, the system identifies the lowest numbered unused NX layer and the DXF/DWG layer maps to that NX layer. A part attribute also adds to the NX part that stores the NX layer number and the original DXF/DWG layer name.</p>
            <p class="para_item">For example, if the DXF/DWG file had 2 layers, 1 and test; 1 would map to NX layer 1. DXF layer test would get mapped to the first vacant or unallocated layer such as NX Layer 2. Additionally, a part attribute would get created that has a title of LAYER_002 and its value would be test.</p>
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            <p class="para_item">Total number of layers exceeds 256.</p>
            <p class="para_item">In this case, a unique mapping for each layer is not possible. All DXF/DWG layers that represent numbered NX layers will map first. All the remaining DXF/DWG layers map to NX layer 256. All objects that reside on these remaining layers (beyond 256), that are created in NX (on layer 256) have an object attribute assigned to them that has a title of LAYER.&nbsp;The value of the attribute is the original DXF/DWG layer name. No part attributes would be created for these additional layers.</p>
            <p class="para_item">One limitation is that DXF layer names can be 255 characters long, but NX attributes can only store the first 132 characters, so some DXF layer names could truncate in rare circumstances.</p>
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      <div class="title_division">Export layer processing</div>
      <p class="para_division">First, NX layers map to their corresponding string equivalents in DXF/DWG. For example, NX layer 2 maps to DXF/DWG layer 2.</p>
      <p class="para_division">If a part attribute exists that has a name similar to LAYER_nnn, then the system will use the value of that part attribute for the DXF/DWG layer name, instead of the NX layer (as described above). For the example given for import example above (less than 256 layers) the NX part when exported would cause NX layer 2 to map to DXF/DWG layer test (since a part attribute of title LAYER_002 exists).</p>
      <p class="para_division">If the NX part has objects on layer 256, the above steps carry out to get the layer name. &nbsp;Further, a check completes to see if the object has any attributes with a title of LAYER. If it finds one, the system will use the string value of that attribute as the DXF/DWG layer name for that object.</p>
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