ALAR 6712  Studio Workshop Spring 2010

Workshop 12 Notes, March 18, 2010

Basic Lighting Sertup and Rendering Continued with Texture Mapping and Procedure Mapping

1. BASIC LIGHTING SETUP

Reload the file stillLife.dgn from the classes folder.

• Turn on the view attribute "constructions"

• View the two spot lights and one point light already added to the model
  
  
  
  
  
  
  
• Check Settings/Rendering/Global lighting.
  
  
  
  
• Turn off Ambient, Flashbulb and Ssolar light by removing the check from the check-box "On" in the dialog box below OR by double clicking on the light symbols to turn off the ambient, flashbulb and solar lights (shown as "on" below), and to turn on the point light and the two spot lights(shown as greyed out or "off" below).
  
  
  
  
• Under View attributes, turn off constructions so as to hide the light fixtures (the lights will still impact the rendering of the model) and to prepare for rendering the model.

3. SAVING RENDERINGS

• Get the View size through the Microstation menu sequence Settings>Rendering>View size.
  
  
• Select the "standard" menu and select mid-resolution  640x480 
• Turn off " proportional resize" 
• Save image file by going to Utilities>Image>Save (check options and save by browsing to folder).

• Note that file type is set to jpg a "pseudo" 24 bit color format to optimize file size against image quality, adequate for school related uses and recommended for making files portable.
• Alternatively "tiff"  format, true 24 bit color, is recommended for higher color quality used in professional printing.
• The view number "2" is indicated to determine which view is to be rendered.
  
• Antialiasing quality is set to "Very HIgh".
• Image size is given in pixels. 
• Select the save button to save the image and  determine its file name and location.
  
• To see image in Microstation, go to Utilities>Image>Display .

5. FILE TYPES FOR MATERIALS (REVISITED)

The Materials Table, Palette and individual images used to define materials can all be potentially saved as external files  so as to be able to be used in other drawing files. When the external file saving option is used, then these file types have standard naming extension formats:

Materials Table (file extension " .mat" )

• References the palette files and tracks assignment of  individual materials.

Material Palette File (file extension " .pal" ) –definition of materials. Can be one of three types

• Definition by properties [e.g. color]
• By procedure [by specific algorithm]
• By texture mapping [literally draping image onto a surface]

Material Photographs

• for using real photographs of materials or people, usually jpg or tiff files are also included in the files needed to define materials (see classes folder Examples\Materials).

6. SIMPLE MATERIAL ASSIGNMENTS (REVISITED)

Go to the Define Materials Icon in the Visualization task:

           

• The l"Define Materials" icon will open the Material Editor. Turn on all the settings "Advanced Mode", "View Samples", and "View Descriptions" as depicted below.
  
  
  
  
• Go to Palette>New menu, create a new palette and name it "mypal"

• Right click on mypal, select "new material", and name it "grue" (this is an arbitrary name)

• Right-click on the pattern check box, and find your way to the materials folder and select the jpg file name rug03.jpg.
  
  
  
  
• In the "Pattern for grue" dialog box that follows, the jpg file is sized to the Units of  "Surface" and will stretch to any surface onto which it may apply. This is the default setting which is OK for this example. Select the "x" in the upper-right hand corner of the dialog box  to go back to the Material Editor window:
  
  
  
  
• Right-click on "grue" in the Material Editor dialog box, go to " Assign," then choose the rectangle in the ground plane from the drawing view window. The material should then have a " +" next to it and contain the layer and color of the object selected.
  
  
• The model will then render in raytrace mode with the rug showing as follows:

• Create a second material named "mybrick" and use the "Pattern for mybrick"  dialog  to choose the material "jamestchapelbrick", and set the size to "master", and the Mapping to "Cubic"
  


• Then rendering will now be as follows:
  
  
• Note that there are some problems with the texture map for brick as captured in the initial photograph. The brick appears self-evidently to be repeating as applied to the cube in a way that seems artificial. For a more realistic rendering of brick, a procedure map (an algorithmically based description)  of brick is used as an alternative.
  

7. PROCEDURE TEXT FILE

Go the the Palette menu and use the "load" tool to open the palette named "proctext.pal"

• In order to preserve the system version of this palette, it is useful to save a uniquely named copy. 
• Right-mouse-button click on the name proctext in the "Material Editor" dialog box and use the "Save As" option to save it to a unique name such as "myproctext.pal".  Any material to be used should also be copied and renamed as in the next two steps.
• Right-mouse button click on the material "Flemish Bond" and select the copy option.
  
  
• Right-mouse click on the palette name "myproctext" and select the paste.
  
   
• Rename the material "myflemishbond" and then select the color square on the right hand side of the dialog box. 
• Select the box adjacent to the word "Pattern" to begin to edit the parameters for the procedure map.
  
  
• Change the "Units" to "Master" so that the pattern maps to one square foot.
• Change the  "Mapping" to "Cubic"  so that the pattern projects appropriately on to the cube.
• Select the "Brick Color" box, and lower  the "value" and lower the "saturation" of the color.
  
• Increase the "Brightness variation" to accentuate differences in dark and light colored brick.
• Increase the "Horizontal variation" to give an uneven look to the horizontal grouting. 
• Increase the "Nosiness" to establish a more weathered look. 
• These adjustments are evident in the Preview window below.
  
  
• Assign the brick to the cube in the Microstation drawing and render a quictk test with "Antialiasing" set to "none".
  
  
•  The apparent  imperfections of the brick rendering can be addressed by fine tuning the ray trace settings. 
• Select the magnifying glass icon next to the word "Untitled" in the Render dialog box, to view the ray trace settings.
  
  
• Within the Render Settings dialog box below,  select "Settings" and select advanced.
• In the "Render Mode" tab, turn on "Multilevel Texture Interpolation" to improve the rendering of the flemish bond. 
• Turn on "Quick Display" so as to render the image in several passes rather than at once. This allows you to abort a rendering by rick-mouse-click in the view window before it is fully executed and will save time if it appears that the rendering is not likely to achieve the results you want.
  
  
  
• In the "Antialias" tab, set "View Quality" to "Very High".
• Set "Jitter Samples" to on.
• Set "Depth of Field" to on to simulate the depth of field effect in a photograph and also set the FStop value to also simulate this setting on a camera. The FStop is set to 5.6 in the example below.  (The lower the FStop value, the more open the camera aperature and the lower the depth of field).
  
  
• Re-render the image to see the change in quality as realized through the above adjustments.
  
  
• Right-mouse-click on "mypal" and create a new material "mywater" in the palette "mypal".
  
  
• Change the color to dark gray, lower the "Diffuse level light towards "Dark", increase the "Specular" level towards "Shiny", increase the "Reflect level" towards "Full", and decrease  the "Opacity" level towards "Clear".
• Change the preview "Display" type to "Sphere".
  
• Add a "Bump" map such as "RoughBump" by selecting the box icon adjacent to the word "Bumpy".
  
  
  
  
• Right-mouse-click on "mywater" and apply the material to the ground rectangle in the Microstation view window. 
  
• Rendering the view indicates some less than fully satisfactory representation of water.
  
  
• Increasing the intensity of the bump map,  as was as "Specular", and "Reflect" produces a potentially more satisfying result.
  
  
• Note that continuous adjustment of values by trial an error may be necessary to arrive at the most desired results. We will later explore the technique of "reflection mapping" that may also help to improve upon the representation of the water.
  
  

8. MODIFY PROCEDURE TEXTURE MAP & CREATE YOUR OWN

In step 7 you had acquired the procdure texture map via the palette> open sequence:

(the palette is located in C:\Documents and settings\All Users\Application Data\Bentley\Workspace\System\Materials).

• You might continue to "save as" the palette as myproc.pal in your local c: drive (or local t: drive if using a School of Architecture computer).
• This includes your copy of the brick (Flemish bond) and renaming it (e.g., "myflemishbond).
• Note that have renamed the material andthe palette file so as to conflict with the system version of this file.

9. SAVING THE MATERIALS TABLE AND PALETTE FILES

Optionally, save the Material Table and Palette to external files.

• In the new palette, right-click on the table name "stillLife"
• Select the Local Material/Export option.
• Export to either a single material table and multiple palettes,  or to a single material table and unified palette file.