Capturing Simple Images

This task explains how to capture simple images as a whole.
  You may find it useful to read the information below before capturing pixel or vector images:

Pixel images

  • Cast shadows cannot be captured.
  • If the visualization mode has been switched to Hidden Line Removal (using Tools > Options > Customize > All Commands) to improve performance, pixel images are captured by replacing Hidden Line Removal by Dynamic hidden line removal (available in the View Mode Customization dialog box). In this case, the two rendering styles give very similar results, the only difference is that Dynamic hidden line removal is a lot faster. To avoid this replacement and generate a pixel image with the Hidden Line Removal rendering style, use the CATPrintRasterNoForcedHRD=1 variable.

Vector images

  • In Shading rendering mode, in which edges are not displayed, capturing vector images is not useful, and produces images that cannot be viewed in the album: you capture only lines and edges in vector mode, not shaded surfaces.
  • Except for the HRD rendering mode, vector images are captured in Shading with Triangles rendering mode.
  • In HRD (Dynamic Hidden Line Removal) rendering mode, vector images are captured in real HLR mode and thus, may look rather different from what you see on screen. 

  1. Select Tools > Image > Capture to display the Capture toolbar:

    The command activated by default in the Capture toolbar depends on the command last used for capturing:
    • If Pixel Mode was activated last, then it is activated by default when displaying the Capture toolbar
    • If Vector Mode was activated last, then it is activated by default when displaying the Capture toolbar.
    In non-standard scale mode (i.e. when Small Scale is selected in Tools > Options > General > Parameters and Measures > Scale), you can only capture images in Pixel Mode. Therefore, the Vector Mode icon (in the Capture toolbar) and the Vector tab (in the Capture Options dialog box detailed below) are grayed out.

  2. Click Pixel Mode or Vector Mode to choose between a pixel or a vector image.

  3. Click Options to access the Capture Options dialog box.

  4. In the General tab, set the following options:

    • Select the Show banner check box if you want to show a banner on the capture. This activates the Banner box containing the $NAME, $DATE and $TIME variables which, by default, print your username, and the current date and time in the banner at the bottom of the capture. This box is editable: you can delete the variables if required and replace them with a text of your choice.
    • Select the Capture only geometry check box if you want to capture the geometry without the specification tree. Note that this option cannot be used for Screen Mode.
    • Choose the Color mode from the list: either Color, Greyscale or Monochrome.
    • Select the Capture white in black check box if you want white pixels to be in black color on the resulting capture.

  5. Access the Pixel tab if you are capturing pixel images, otherwise jump to step 7:

    • Select the White background check box if you want the capture to be taken on a white background.
    • Select the Anti-aliasing check box to modify the appearance of lines in order to make the jagged edges look smoother.
      This anti-aliasing filter is independent from the anti-aliasing mode available in Tools > Options... > General > Display > Visualization. When using the capture tool, only the anti-aliasing filter available in the Capture Options dialog box is taken into account.
    • Select the Constant size capture check box if you want the DPI and the resolution to increase with the quality (i.e. the higher the quality, the higher the DPI and the resolution), so that the captured images always have the same size in millimeters.
    • Set the Rendering quality factor which determines the quality of the output:
      • Low (screen): the quality of the output matches the screen resolution. This is the default value
      • Medium
      • Highest
      • Customized.

      The higher the setting, the greater the quality of the capture.

    Selecting Customized in the Rendering quality list (where you see Low (screen) right now), activates the More... button which lets you access the Image Size dialog box:

    This dialog box enables you to define the print Width, Height and Resolution:

    • First, choose the Resolution, either in pixels/inch (.dpi) or in pixels/cm. The higher the resolution, the longer the capture generation (with a price to pay in performance).
    • Define the print Width and Height. The maximum value you can set is 30000 x 23837 on Windows and 10000 on UNIX (the previous maximum value was 8000 x 6543).
      If the value you set exceeds the amount of allocated memory, captured images are stored in temporary files in C:\Documents and Settings\user\Local Settings\Temp on Windows and /tmp on UNIX. These files are named capture_hour.bmp, for instance, "capture_15.42.30.bmp". Images stored in a temporary folder can be saved only in BMP format on Windows and UNIX.
      Regarding fill patterns printed in HPGL2, PDF or PostScript format, note that if the size of the computed image exceeds the amount of allocated memory, then the allocated memory is reduced by setting a lower dpi value and therefore, the rendering might be different from the one expected.

    The values indicated in the Pixel Size area are displayed for information only to give you an idea of the image size in pixels, according to the print size you defined.

    If the Monochrome color mode has been selected in the previous step, you can use the Monochrome Filter list to select the type of filter to be applied:

    • Dither: default filter based on the Floyd-Steinberg algorithm often used to do the dithering to transform color images into black and white images.
    • Threshold: a simple algorithm based upon a threshold corresponding to the average of the colors inside the image: if the color value is up from this threshold it is transformed into white, otherwise it is transformed into black. This algorithm sometimes avoids bad effects on line rendering in black and white.

    Black and white render with Dither algorithm:

    Black and white render with Threshold algorithm:

  6. Click Album... to define your preferences for storing the images you are going to capture in the album:

    First, select the desired file format from the Format list. Then, select the compression type: 
    • No compression (if you do not want to compress the file). This is the default option
    • Packbits
    • JPEG
    • HUFFMAN
    • Fax Group 4.

    When you select the JPEG compression type, the Quality slider is activated to let you define more precisely the compression quality (from 0 to 100 %). The higher the value, the better the quality.

  7. The Vector tab lets you set the following options:

    • select the Semantic Level type which enables you to choose the rendering mode:
      • Discretized  (i.e. when the image suffers from a lack of points, points are distributed to fill the gaps and ensure linearity)
      • Low
      • Polyline
      • Polyline and Conic
      • Polyline and Spline.
    • select the format from the list: either CGM or Generic PostScript, then set the properties for the chosen format, if necessary:
      • If you select CGM, clicking Properties... opens the Advanced Configuration dialog box:
        This dialog box contains four tabs which let you define the various parameters associated to the CGM format.
      • If you select Generic PostScript, clicking Properties... opens the following dialog box:
        You can choose the desired level for PostScript generation and activate the Encapsulated PostScript (EPS) format as well. EPS does not contain page description directives and is designed for portable exchange between applications and platforms. It may also be included in a larger PostScript document.

      Note: captured images saved in the album are always saved in CGM format. The properties you define in the Capture Options dialog box have no impact on the format of the image stored in the album. These properties will be applied to the format you select when using the Save As button in the Capture Preview window (as explained below).
      Therefore, to save an image in Generic PostScript format, select Generic PostScript in the Capture Options dialog box and define the level to be used then, when the image is captured, click the Save As button to select the image format.

    • When capturing a document in Vector mode, the size in mm of the generated 2D document depends on the size you select in the Capture Size list:
      • Model size means that the size of the image corresponds to the size of the model. For instance, if the captured model is a 10 mm coin of 1 Euro, then the size of the captured image will be 10 mm.
      • Display size means that the size of the image corresponds to the size of the model as displayed on screen. For instance, if the captured model is a coin of 1 Euro and it is zoomed to a size of 200 mm on screen, then the size of the captured image will be 200 mm.

  8. Once you are satisfied with the parameters, click OK to validate.

  9. Click Capture to capture the image and store it in the album. A progress bar appears while the captured image is generated. 

    When the captured image is generated, the Capture Preview window opens:
    The Capture Preview window provides a preview of the captured image that will be stored in the album when you click Album .

    This window also enables you to use the following icons to:

    • cancel the image (and close the Capture Preview window).
    • save the image under another name and/or another format. To do so, click the Save As button, give a name to the image then navigate to the desired location before clicking OK to confim the save. Refer to Saving Images to Other Formats for detailed information.
    • print the image. Clicking this button opens the Print dialog box. Refer to Customizing Print Settings for detailed information.
    • copy the image to the clipboard.
    • open the album.

  10. Click Album to store the image in the album.

    Note that images captured in Vector Mode are saved on a 1:1 scale and not in A4 format anymore.

  11. Click Open Album or select Tools > Image > Album to display the album.

    The album is displayed, listing the current contents of the album.
    For detailed information on how to display and edit images in the album, refer to Previewing Images in the Album and Editing Images in the Album.

The contents of the album are stored on your system in a non-editable file in the location defined by the CATTemp environment variable. Deleting this file deletes the contents of the album.