How to view CAD documents using Java Leave feedback

CAD (Computer-Aided Design) document formats are designed to work on detailed drawings, building plans, and device diagrams for their subsequent production or related work. What used to be done manually on a drawing board in pase, now can be done quickly on a computer. The most used formats in the CAD design industry are DWG, DWF, DXF, DGN. In this article, we will discuss how to view CAD files in Java applications.

The following topics are covered below in brief:

• Java API for rendering CAD files
• How to render CAD files into HTML, JPG, PNG, or PDF
• Getting layouts/layers information
• Layers rendering
• Layouts rendering

GroupDocs.Viewer for Java provides API to render CAD documents formats to PNG, PDF, JPEG, and HTML. Also, API includes special options for additional result image processing. Supported formats are DWF, DXF, DGN, IFC, STL, DWT, Plotter documents, and many others.

Follow one of the ways as described in the Installation section to install and reference GroupDocs.Viewer for Java.

To render your file to HTML file(s) with embedded resources do the following steps:

• With Viewer class load your document.
• With the forEmbeddedResources method create the HtmlViewOptions instance and type output file name.
• Call view method to render your document to HTML, resources will be embedded in to file.

try (Viewer viewer = new Viewer("sample.dwf"))
{
    HtmlViewOptions viewOptions = HtmlViewOptions.forEmbeddedResources("page_{0}.html");
    viewer.view(viewOptions);
}

To render your file to HTML file(s) with external resources do the following steps:

• With Viewer class load your document.

• with forExternalResources method create HtmlViewOptions instance and type:

  • the output file name mask
  • external resources folder file path mask
  • url for resources mask format

• Call view method to render your document to HTML.

Resources will be placed to separate folder.

try (Viewer viewer = new Viewer("sample.dwf"))
{
    HtmlViewOptions viewOptions = 
        HtmlViewOptions.forExternalResources("page_{0}.html", "page_{0}/resource_{0}_{1}", "page_{0}/resource_{0}_{1}");

    viewer.view(viewOptions);
}

• With Viewer class load your document.
• Сreate JpegViewOptions instance and type output file name.
• Call view method to render your document to JPEG.

try (Viewer viewer = new Viewer("sample.dwf"))
{
    JpgViewOptions viewOptions = new JpgViewOptions("page_{0}.jgp");
    viewer.view(viewOptions);
}

• With Viewer class load your document.
• Сreate PngViewOptions instance and type output file name.
• Call view method to render your document to PNG.

try (Viewer viewer = new Viewer("sample.dwf"))
{
    PngViewOptions viewOptions = new PngViewOptions("opage_{0}.png");
    viewer.view(viewOptions);
}

• With Viewer class load your document.
• Сreate PngViewOptions instance and type output file name.
• Call view method to render your document to PDF.

try (Viewer viewer = new Viewer("sample.dwf"))
{
    PdfViewOptions viewOptions = new PdfViewOptions("output.pdf");
    viewer.view(viewOptions);
}

CAD files often consist of many layouts and layers. You can obtain information on what layouts and layers are in a specific file with the following code:

• With Viewer class load your document.
• Сreate ViewInfoOptions instance using ViewInfoOptions.forHtmlView() method.
• Call getViewInfo to get layers/layouts information and get CadViewInfo object result.
• Layouts and layers Lists are located in resulted CadViewInfo object.

try (Viewer viewer = new Viewer("sample.dwf")) {
    ViewInfoOptions viewInfoOptions = ViewInfoOptions.forHtmlView();
    CadViewInfo viewInfo = (CadViewInfo) viewer.getViewInfo(viewInfoOptions);

    System.out.println("File type: " + viewInfo.getFileType());
    System.out.println("Pages count: " + viewInfo.getPages().size());

    for (Layout layout : viewInfo.getLayouts()) {
        System.out.println(layout);
    }

    for (Layer layer : viewInfo.getLayers()) {
        System.out.println(layer);
    }
}

You can use this information to specify what layers/layouts render in the output file.

File type: Design Web Format File (.dwf)
Pages count: 3

Layouts:
three-layouts-with-layers-Layout1 8.40063667297363x6.40062713623047px
three-layouts-with-layers-Layout2 8.40063667297363x6.40062713623047px
three-layouts-with-layers-Layout3 8.40063667297363x6.40062713623047px

Layers:
CIRCLE (visible)
0 (visible)
TRIANGLE (visible)
QUADRANT (visible)

CAD drawing most often contains multiple layers, drawing contains a list of layers that rendering by default, but other layers may hidden, because these layers are may contain supervisor remarks, details of the discussion, or other additional information that should not be in the final drawing.

To render your file with specific layers please do the following steps:

• With Viewer class load your document.
• Сreate HtmlViewOptions/JpgViewOptions/PngViewOptions/PdfViewOptions instance and type output file name.
• Specify layer(s) to render.
• Call view method to render your document with specified layers.

try (Viewer viewer = new Viewer("sample.dwf"))
{
    HtmlViewOptions viewOptions = HtmlViewOptions.forEmbeddedResources("page_{0}.html");
    viewOptions.getCadOptions().getLayers().add(
        CacheableFactory.getInstance().newLayer("CIRCLE")    
    );
    viewer.view(viewOptions);
}

This drawing contains two layers: “0” - with a rectangle and “CIRCLE” with a circle. We want to render circle only, so we added a layer with the name “CIRCLE” in the layers list.

By default GroupDocs.Viewer renders CAD file model presentation (document default layer). If you want to choose a different layout you can set the layout name to render.

To render your file with specific layouts please do the following steps:

• With Viewer class load your document.
• Сreate HtmlViewOptions/JpgViewOptions/PngViewOptions/PdfViewOptions instance and type output file name.
• Set required layout name by calling viewOptions.getCadOptions().setLayoutName() method.
• Call view method to render your document with a specified layout.

try (Viewer viewer = new Viewer("sample.dwf"))
{
   HtmlViewOptions viewOptions = HtmlViewOptions.forEmbeddedResources();
   viewOptions.getCadOptions().setLayoutName("three-layouts-with-layers-Layout2");
   viewer.view(viewOptions);
}

This drawing contains three layouts: “three-layouts-with-layers-Layout1”, “three-layouts-with-layers-Layout2”, “three-layouts-with-layers-Layout3”. We select “three-layouts-with-layers-Layout2” layout name with rectangle, we set this layer name in LayoutName property.

In order to use the API without evaluation limitations, you can get a free temporary license.

In conclusion, I hope you now know how to view CAD files in Java applications, in this article you have seen how to get models, layers, and layouts information for CAD files in your application. Also, you can use Online apps to view your files these applications are built based on GroupDocs.Viewer.

You can learn how to use GroupDocs.Viewer in your applications with documentation and if you have any questions or issues you feel free to send these via our forum.

• How to view Word documents using Java
• How to view PDF documents using Java