3D Scanning at NPL

• Before starting, create a file folder on your desktop for saving temporary files. Name it something along the lines of Temp 3D Cache.

  • Press Edit → Preferences → Browse and select this folder. All autosaves and temporary data caches will be directed here.

• Determine whether you want ScanStudio to autosave after every process. It generally isn’t advised, because it consumes a lot of time and creates an unnecessary amount of files.

  • To toggle autosave on or off, press Edit à Preferences, and check the box Enable Model Backups.

• Save frequently, at least after every few steps performed. ScanStudio has a tendency to crash unexpectedly, and it’s very easy to lose data and time.

• To save a model, press File → Save As… from any screen in ScanStudio. By default, models are saved as .scn files.

• When performing a save, always create a new folder to save the model into, (within Temp 3D Cache folder). It’s easiest to name these sub-folders Project 1, Project 2, etc.

  • Saved models save texture files, (as .jpg’s), alongside the .scn file, as well as some .raw files.

  • A .scn file must be in the same folder as its associated .jpg’s for the texture to appear on the model in ScanStudio.

• If multiple models are saved into the same folder, ScanStudio can confuse their associated texture files, creating a multitude of glitches, including loss of texture data. Saving each file in a separate folder alleviates this issue.

The following is a guide indicating the necessary steps of completing a 3D scan. This does not does not describe every option available in ScanStudio. See Additional Post-Processing for descriptions of other, less necessary options available in ScanStudio not described here.

Step 1: Select the specimen to be scanned

I: Small to medium-sized (fist sized) specimens are easiest to scan. Larger specimens become increasingly difficult to scan, and create proportionally larger file sizes, slowing down the program.

II: Avoid glossy or otherwise reflective specimens. The lasers have a difficult time detecting the surface of these specimens. Avoid specimens with translucent surfaces for a similar reason.

• If a glossy or translucent specimen must be scanned, smoke or pigment it beforehand

III: Dark-colored specimens tend to scan better than lighter colored specimens.

IV: Avoid specimens with a large amount of internal structure. The lasers have a difficult time penetrating beyond the surface of most specimens, even if it seems like it should be able to.

V: Avoid exceptionally fragile specimens

• If a highly fragile specimen must be scanned, ensure beforehand that it properly consolidated

Step 2: Open the ScanStudio program

Step 3: Position the specimen on the stage or scanning surface

I: Press the green Scan button in the tool bar. This will open a separate scan screen. The right hand of the screen will be occupied by a preview window that shows you what the scanner can see. Use this for reference when adjusting the position of the specimen.

• Try and maximize the amount of specimen surface exposed to the scanner. Often this is achieved by positioning the specimen at oblique angles, though it depends entirely on the specimen being scanned.

II (A): Small and medium sized specimens can be placed on the accompanying stage.

• Small specimens can be placed on the elevated stage. Secure the specimen using the adjustable arm attached to the pole. Prop up the specimen with clay as necessary to ensure the specimen is stable.

• Medium-sized specimens can be placed on the larger stage base. In this case, unscrew the elevated stage from the base and set it aside. You won’t have access to the adjustable arm in this configuration, so make extra-sure the specimen is stable on the stage base before beginning scanning. If the stage base is too low for the scanner to see, elevate it on a box or other stable elevator.

II (B): Large specimens may have to be placed on a scanning surface other than the stage

• If a specimen is too large for the accompanying stage, place it on a secure surface, such as a nearby table, lined with foam.

• Make sure the background the specimen is lying on or propped up against contrasts the color of the specimen.

• Specimens scanned in this configuration will not be able to rotate, and will only be able to be scanned through a series of single scans. This will negatively affect the quality of the surface color, and can be more time consuming. Take this into account before starting.

III: Adjust the distance of the scanner from the specimen and select the appropriate setting.

• Macro - Most small and medium-sized specimens will be using the Macro setting in the scan settings. For specimens of this size, the front surface of the specimen, (the surface of the specimen facing the scanner), should be at least 7.5 in. from the scanner. 9.5 in. from the scanner is the ideal distance. The specimen should be no more than 11.0 in. away from the scanner.

• Wide - If a specimen doesn’t fit within the scan preview window with the Macro setting selected, then it is likely too large for the Macro setting. For specimens of this size, the front surface of the specimen should be at least 22.0 in. from the scanner. 25.0 in. from the scanner is the ideal distance. The specimen should be no more than 28.0 in. away from the scanner.

• Extended - For particularly large specimens, the Extended setting can be used. For specimens of this size, the front surface of the specimen should be at least 22.0 in. from the scanner. 25.0 in. from the scanner is the ideal distance. The specimen should be no more than 40.0 in. away from the scanner.

• Note: specimens, (or parts of specimens), which fall outside the range of a particular scan setting will see a dramatic drop in scan quality. Always try and make sure the specimen falls within the appropriate range of distance. The further the specimen is from the scanner, the lower the quality of the surface detail will be.

Step 4: Adjust scan settings and begin scanning

I: Press the green Scan button in the tool bar (if you haven’t already) to open up the scan screen. Keep Scan Family set to Auto.

II: Select the type of scan Positioning

• 360 – This scan type cause the stage to rotate a full 360°, in increments equal to the number of Divisions you have selected (see Step 4; III).

  • Only specimens small enough to be safely placed on the rotating stage can be 360 scanned.

• Bracket – This scan type causes the stage to rotate partially, based on the number of Divisions you have selected (see Step 4; III). This allows you to only scan a particular section of the specimen.

  • The axis facing the scanner acts as the center point of rotation for the stage.

  • The angle of stage rotation is inversely related to the number of Divisions you have selected. The greater the number of Divisions, the lower the angle of rotation. (Example: 16 Divisions = 1/16 rotation, 4 Divisions = 1/4 rotation, etc.)

  • 3 scans will always be taken – one at the widest left angle, one along the center axis, and one at the widest right angle.

  • Only specimens small enough to safely be placed on the rotating stage can be Bracket scanned.

• Single – This scan type takes a single scan of the specimen, regardless of the number of Divisions selected. The stage does not rotate.

  • This scan type is most useful for scanning specimens too large to fit on stage, and to fill in unscanned sections of smaller specimen.

III: Select number of Divisions.

• This number will determine the number of scans taken in a 360 scan, and the angle of rotation in the Bracket scan. It has no effect during a Single scan.

IV: Select Points/in²

• This value defines the overall quality of the scan. The higher the value, the higher fidelity the scan will be.

• This value varies based on the Range setting selected

  • Macro – 1.2k Points/in² – 268k Points/in² (highest quality)

  • Wide – 125 Points/in² – 29k Points/in²

  • Extended – 14 Points/in² – 3.3k Points/in² (lowest quality)

  • Note: Avoid setting to the highest Macro value (268k Points/in²). This will slow down the program and make your model file unnecessarily large without any noticeable increase in quality. The second highest value (67k Points/in²) is generally high enough.

V: Select Target color

• Select the color type that best matches the color of the target specimen. For white or light-grey specimens, select Light. For grey, tan, and light-brown specimens, select Neutral. For black or dark-brown specimens, select Dark.

  • Note: Dark specimens tend to scan better than light specimens.

VI: Select the appropriate Range, if not done so already (See: Step 3; III). This is the distance the specimen should be placed away from the scanner.

• Macro – 7.5  in. – 11.5 in. from scanner. 9.5 in. is ideal.

• Wide – 22.0 in. – 28.0 in. from scanner. 25.0 in. is ideal.

• Extended – 22.0 in. – 40.0 in. from scanner 25.0 in. is ideal

VII: Use the grey Turn buttons at the top of the screen to double-check that the specimen remains visible to the scanner throughout the entire scan within the preview window

• As the stage spins, the specimen may fall into or out of the visibility of the scanner. Spinning the specimen allows you to see what the scanner will see at every point in the scan via the preview window.

  • Click the arrow buttons to turn the stage a small amount clockwise or counterclockwise

  • Click the vertical rectangular button to turn the stage one quarter turn clockwise or counterclockwise

  • Hold down the arrow buttons to perform a single, continual turn clockwise or counterclockwise. The stage will stop spinning when it reaches its starting point.

• Drag and pull with the mouse in the preview window to constrain the size of the area scanned, (delineated with a dotted-lined box). This allows you to cut out background and superfluous information, reducing scan time and file size.

VIII: Press the green Scan button at the top of the screen to start the scan

• Note the time and memory values (represented at the bottom left of your screen) before starting.

  • Time – This gives you an approximate time for how long the scan should take. It is not 100% accurate. Expect the actual time to be at least several minutes longer than the time presented. It may take even longer if the memory usage is particularly high.

  • Memory – This is how much available RAM is being used by ScanStudio. The closer the memory usage is to 100%, the longer the scan will take, and the slower your computer will perform during the scan. This will also increase the likelihood of the program crashing during your scan.

• Upon beginning the scan, the program will return you to the main screen.

• While a scan is occurring, you can continue navigating the program, including rotating and manipulating the existing model. This is not recommended. The program may crash if you continue using it while a scan is being performed, so it’s best to minimize it and not use the program while a scan is running.

• For very large specimens and other scans with a lot of data, the entire computer may become slowed by the program, and using other programs on the computer may slow down the scan or cause the program to crash. In these cases, it’s best to not use the computer for other functions while performing a scan.

• A scan in progress can be stopped by pressing the red Stop button, or by pressing Scan → Stop a 3D scan… in the menu bar, but it is finicky. Sometimes pressing the button simply doesn’t work, other times it will crash the program.

• Note: While a scan is being performed, avoid bumping the specimen, stage, or table. Keep lighting consistent, (don’t turn the overhead lights on or off). Don’t let anything pass in front of the lasers or obstruct the view of the NextEngine.

• Note: Completed scans are stored as scan families in the view bar across the bottom of the screen.

  • The number of individual scans in a Scan Family is equal to the number of Divisions for 360 scans. For Bracket scans, there will always be 3 scans in a Scan Family. For Single scans, there will only be 1.

  • You can move Scan Families in and out of the green active scans box in the bottom left of the screen. Multiple, attached scans can occupy this space at the same time (See: Step-by-Step Guide; Step 6). Scans should only be attached after they’ve been aligned.

  • Double clicking on any scan family allows you to see and work with each individual scan, including deleting, trimming, fusing, aligning, etc. Pressing Up will collapse the individual scans back into the original Scan Family. It’s rare that you’ll have to interact with scans in this way.
    
    

Step 5: Trim excess data

I: Press the blue Trim button at the top of the screen. This will take you to a separate trim screen.

II: Select the parts of the model you want to delete using the tools available in the toolbar at the top of the screen

• Pointer mode – This tool allows you to rotate the model as you would normally. Within the trim screen, this tool must be selected to rotate the model. The model may still be shrunk or enlarged using the scroll wheel on the mouse from any tool mode.

• Circle brush selector – A basic circular selector tool. Pressing the mouse allows you to ‘paint’ areas of data you intend to delete. These areas will be colored in red.

• Square brush selector – Identical to the Circle brush selector, but square. Useful for more angular models.

• Rectangular region selector – By holding down the mouse and dragging, you can create a box of any size. Anything inside the box when you release the mouse will be selected.

• Polygon region selector – By clicking the mouse at arbitrary points, you can create a polygon of any shape. When you place a point (the final point) on your starting point, anything inside the polygon will be selected.

• ALL – Pressing this button will select the entire model.

• De/Select – Allows you to switch between selecting data to delete and deselecting data you do not want to delete.

  • ( – ) – This is the default selection. Any data you select while in this mode will turn red to indicate it is ready to be deleted.

  • ( + ) – This mode allows you to de-select data you have already selected.

III: Press the blue Trim button at the top of the screen when all of the excess data has been selected

• This will trim any data you have selected in red

• This process be undone via the Re-Generate Scans option, (See: Additional Post Processing; Re-Generating Scans), but the restored data may be corrupted. Always double check before trimming to make sure you’re not trimming relevant data. Assume it’s irreversible.

• Note: Sometimes excess data can be hard to see. Switch between the View options in the bottom right of the screen to check and make sure all of the appropriate data has been deleted. The Mesh view is particularly useful for spotting stray bits of data on a dark background. (See: Introduction; View Options)

• Note: Another hint for telling that all excess data has been deleted is by rotating the model. A model will tend to rotate near its center of mass. If a model is rotating at a point outside of the model itself, it means there is stray data separate from the main body of the model that needs to be trimmed.

• Note: Avoid trimming aligned or fused models when possible. Trimming these models takes substantially longer than trimming a single scan family.

IV: Press the blue Back button at the top of the screen to return to the main screen

Step 6: Align your scan families

I: Ensure you have at least two completed scan families to align. Scan families are aligned two at a time, regardless of how many you have.

II: Press the blue Align button at the top of the screen. This will take you to a separate Align Screen.

III: Press Edit → Preferences → Align Settings in the menu bar to adjust the alignment settings as necessary. (See: Settings and Preferences; Alignment Settings)

• Most of these settings can be kept as default, but may need to be adjusted if the alignment is running slowly, or if the program is misaligning your scan families.

IV: Select the scan families to align. The scan family currently occupying the green active scans box will occupy the left half of the screen. The right half of the screen will be occupied by whichever other scan you have selected.

V: Place pins on each model at corresponding surface features of each model.

• Drag and drop pins from the top left of each portion of the screen onto surface features of each model. Make sure pins of the same color correspond to the same feature on either model

• A minimum of three pins must be used for alignment to work properly, but as many pins may be used as necessary.

  • After placing three pins, three more will appear for use, if you need them.

  • It isn’t recommended you place too many pins. The more exact you try to make the manual alignment, the more likely the alignment is to be off. Three pins is generally adequate.

VI: Press the blue Align button to begin the automatic alignment

• If nothing happens when you press the button, first click in the left-hand side of the screen, then press the align button again.

• There is no time indicator, but alignment can take anywhere from a few minutes to nearly an hour. It depends on the size of the model.

• When a model is aligned, both Scan Families will occupy the green active scans box together. If the model is misaligned, remove one of the scan families from the active scans box, and try again.

• If a model is misaligned, try placing more pins, or pins on different parts of the model. If misalignment still occurs, you may have to adjust some of the settings. (See: Settings and Preferences; Alignment Settings)

VII: Press Align → Settings when the scan families are properly aligned. This will open a new window. Select the aligned scan families from the appropriate tab, and check Fixed (will not be moved by alignment).

• Checking this box locks the respective scan family’s position, ensuring that aligned scan families will not become misaligned by future additional alignments.

• Repeat this step each time you align a new scan family.

VIII: Press the blue Back button at the top of the screen to return to the main screen

Step 7: Fuse your scans

I: Ensure you have performed all of the scans you intend to perform, and have trimmed and aligned all of the scan families before proceeding.

• You can trim a fused scan or align additional scan to an already fused scan, but it takes much longer. Fusion is generally treated as one of the final steps in a scan.

II: Press the blue Fuse button at the top of the main screen. This will take you to the fuse screen.

III: Press the grey Settings button in the tool bar. This will open a separate settings window. Adjust the settings as appropriate. (See: Settings and Preferences; Fuse Settings)

• Most of the Fuse settings can be kept as default, but if this is your final fusion, make sure Create Watertight Model is selected.

IV: Press the blue Fuse button at the top of the screen to begin the fusion.

• Fusing requires a lot of computer memory to perform. It’s best to close background programs and avoid working on the same computer while a fuse is happening. For large models, this becomes a necessity, as ScanStudio often crashes during this step.

• Fusing is one of the most time consuming steps.

• Once a model is fused, it will create a new Scan Family. The scans that went into making the fused model will still be available in the scan bar at the bottom of the page. If the fusion went poorly, the fused model can be deleted and retried.

Step 8: Remesh the scans

I: Press Polish → Remesh (fill holes)… in the menu bar. This will open up a separate remesh settings window.

II: Adjust the Remesh setting as appropriate. (See: Settings and Preferences; Remesh Settings)

• Most of these settings can be kept as default. Just makes sure the Fill Holes option is checked.

II: Press Remesh to begin remeshing the model.

• Remeshing deconstructs and reconstructs the model. In the process it improves the quality of the mesh, fixes imperfections and misalignments, and fills holes.

• Like fusing, remeshing can take a long time, and puts a strain on the computer’s resources. Avoid performing too many tasks on a computer while a remesh is taking place.

Step 9: Save the final model

I: Press File → Save as… and save a final .scn backup file including the fused and remeshed model, as well as all of the separate scan families.

II: Delete all of the scan families except for the final, fused and remeshed model.

III: Save the final .scn file containing only the fused model. This file should be smaller than the backup. Deleting the excess scan families helps save file space.

IV: Press the blue Output button in the tool bar to save .obj and .stl files

V: Press the blue OBJ file button to save a copy of the model as a .obj file

VI: Press the blue STL file button to save a copy of the model as a .stl file

• When the STL Format Selection screen appears, select Binary, then press OK

Step 10: Update the database record

I: Open Specify

II: Open the appropriate Collection Object record

III: Scroll down to the Preparations section

IV: Add a preparation for the 3D model file

• Set the number of pieces to 0

• Copy the file path into the Preparations Remarks field

V: Save the record