COMPUTER AIDED ARCHITECTURAL DESIGN

Workshop 8 Notes, Week of October 15, 2012

Lighting, Global Illumination Rendering,Texture Mapping and Procedure Mapping

NOTE: To initiate this workshop, you can build the file below in Rhino or copy the fie "Arch3410-6710-Mark-FAL12\examples\rendermodel\stillLife.dgn" and the folder "Arch3410-6710-Mark-FAL12\examples\materials".

1. BASIC LIGHTING SETUP

• Create the file stillLife.3dm in Rhino with a flat plane and three solids. Add three vertical lines at the corners as shown below
• Note, the process is simpler if you hold off on assigning color directly to objects until entering into Microstation. Assign the objects to separate levels in Rhino.

• Open the file in Microstation.
• Save the file to stillLife.dgn Microstation format.
• Change the background to black via the workspace/preferences/viewoptions menu.

• Turn on the view attribute "constructions" from the upper-left hand corner of the active view angle.

• Enter the light manager W1 tool in the Visualization task.
  
  
  
  
  
• Place a rectangle on the ground, and then in separate colors a cube, sphere and truncated cone.
• Add a vertical line to front-left, front-right and back right corners of teh rectangle on the ground.
  
• Add three vertical lines and then two spot lights and one point light to the model  
  
  
  
  
  
  
  
• Turn off the "Constructions" in the view attributes dialog box.
• Check Settings/Rendering/Global lighting.
  
  
  
  
• Turn off Ambient, Flashbulb and Solar 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 ensure that the point light and the two spot lights are turned on.
  
  
  
  
• 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. SETTING THE VIEW SIZE

• 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" 

4. LUXOLOGY RENDERING AND SAVE DIALOG

• Select the "Q1" tool in the Visualization Task.

• Within the Luxology rendering window, choose the Raytrace rendering option.
• Note that an earlier rendering will first show up in the rendering view window, not necessarily your current model.
• Image size is given in pixels in the upper right-hand corner at 700 pixels by 700 pixels (release padlock to set X and Y independently).
  
  
  
• The view number "2" is indicated to determine which view is to be rendered.
• Initiate the rendering.
  
  
  

• Use the save file icon in the lower left hand corner of the Luxology Rendering Window.
  
  
  

• 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.
• Selecting the "Q4" tool, each of the rendering types can be optimizied by determining the appropriate parameters for each.
  
  
  
  
  
• For example, antialiasing quality is set to "Medium" which optimizes quality against renderint time. A setting of "Very HIgh" which requires more rendering time.
  
• For each attribute on the three tabs "Settings", "Global Illumination", and "Advanced", there is often a trade off between rendering quality, realism, and rendering time.
• A discussion of each rendering setup is beyond the scope of these workshop notes, but has been referred to in part in the general overview just before the fall break. The Microstation Help dialog box also contains specific information about each setup. For example, go to the Help/Contents Menu, and initiate a search on "luxology render settings". Look at the 3rd item "Luxology Render dialog".
  
  
  
  
• 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" if saved externally)

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

Material Palette File (file extension " .pal" if saved externally) –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 "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 system folder such as 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 (UPDATED INSTRUCTIONS)

Material tables and palette files are saved internally to the CAD file. However, if you want to reuse the table and palette for a new file, especially one modified andre-imported from Rhino, there are two strategies:

9. a. Save The Material and Palette File through the Assign Material Dialog Box and the Materials Editor

This method preserves the Materials Table and also Palette File Assignments to Materials. In this approach, you need to have both the original and more recent update file available, and you need to follow the entire sequence on the same computer. If you working from your laptap, you can do this procedure without having to have both the older and newer files available at the same time.

Starting with the older file saved to the dgn (Microstation format), once you've concluded making the materials table and associated palette file:

EXPORT FROM INITIAL FILE

• go to the material editor,and select the menu item sequence Palette\local materials\copy to library
  
  
  
  
• next, select the palette you wish to save externally to the dgn file, go to the menu item sequence Palette "saveas" and save the palette file to same folder as the dgn file
• next, go to the "Visualization Task" on the left-hand side of the view window and select the "Apply Material" Icon
  
  
  
  
• in the dialog box that follows, go to last icon to the right of the word"Table" and select it to write the table and associated palette files to an external file:
  
  
  
• the "save as" dialog box appears as follows:
  
  
  
  IMPORT INTO UPDATE FILE
  
  
• Lets assume you modify the original Rhino file and save it to a new microstation file. Now, go to the"Assign Material" dialog box, and choose the yellow-folder icon to open the externally saved material table:
  
  
  
  
• in the file open dialog box that folllows, choose the material table (e.g., "globalModel.mat") saved earlier:
  
  
  
  
• next, within the same assign material dialog box, choose the blue folder icon adjacent to the world "Palette" and load up the palette files saved earlier on at a time
  
  
  
  
  
• returning to the Material Editor, note that the the prior table, associated palette file and material assignments are all restored
  
  
  
  

9. b. Save The Material Table andPalette File Through the Material Table Dialog Box. This is an older method.

Optionally, save the Material Table and Palette to external files if you want to re-use them in other CAD models. Using this method you need to redo the assignments of specific materials to parts of the 3D model.

• 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.