Introduction: 3D Scanning Using the NextEngine 3D Scanner HD
This instructable gives an introduction to using the NextEngine 3D Scanner HD at MAKlab, Glasgow.
There is a PDF tutorial provided by NextEngine that goes into some detail, but it is a little hard to jump straight into scanning from. This guide will hopefully be more useful as a 'Quick Start'.
The golden rule as ever: SAVE OFTEN!
If anyone would like to edit and enhance this guide, just send me a message on Instructables and I'll add your username to the 'collaborators' list so you can make revisions.
Step 1: Setup and What You Need
- Nextengine scanner and turntable (pictured)
- An object to be scanned.
- Dust, paint or other surface treatment may be necessary
- Sticky arrows or other markers for large or complex objects.
Step 2: Set Up for a Scan
Startup NextEngine HD from the desktop on the connected computer.
- The blue light on the top of the scanner should illuminate. If not, check your connections.
- The software environment is very simple: 3D geometry is shown in the main window, all the tools you need are accessed using the top toolbar, which also shows the status of the program. The bottom pane is a library of scans in the current file.
- Click the triangular 'Scan' button in the main toolbar to enter the scan window. The scanner will brightly illuminate the object for setting up.
Setup the object and turntable
- Using a ruler ensure that the centre of the turntable is 17" from the front of the scanner for a normal scan, or 11" for a macro (closeup) scan.
- Place your object in the centre of the turntable. There are various attachments for mounting more delicate objects onto the turntable. These screw into the holes at the corners of the turntable.
- On screen you will see a live video image from the camera in the scanner. Watch this and manually adjust the position of the scanner so that the object is in the centre of the on screen preview. Do not worry if your object does not fit in the preview at the appropriate distance - you can scan different parts of the object and align them together later quite easily.
Step 3: Do a Test Scan
- This area controls the scope of the scan, either single, bracket (3 scans from different angles), 360 (several scans all around the object).
- Divisions determines the angles between scans in bracket and 360 modes - the greater the number of divisions, the smaller the angle between scans.
- Low resolution scans are very crude, so more may be required to capture all the surfaces in any case.
- You can actually change this setting after scanning using Fuse/Regenerate.
- At the bottom of the scan page, the software indicates the estimated time that the scan will take in minutes, and the size of the scan in terms of memory (well, sort of).
Select either wide or macro scanning as appropriate.
- Macro is for very close up scans. check that the distance between scanner and object matches with the advice on screen near these options. Extended mode is not available and requires extra payment (quite a lot I'm told). For large objects you can scan different parts of the object and align them together later quite easily.
- The scanner will illuminate the object, taking a photo first, then scan a laser array over the object. The camera observes the variations in the reflected laser light and the software deduces from this the 3D form.
Step 4: Viewing the 3D Geometry
Now is a good time to File/Save As and give you scan file a name.
One scan only is not much for the software to go on, so you will not see anything impressive from a single scan. However, it is useful for checking that the setup is OK. You should see a fairly faithful representation of a very narrow segment of your object on screen.
You can manipulate the onscreen surface using the mouse buttons and dragging:
- Left click and drag to rotate the scan.
- Right click and drag up and down to zoom in and out respectively of the scan.
- Click both left and right buttons and drag in order to pan the scan.
Step 5: Improving the Scan Quality
Distance from scanner
- Make sure your object is in the centre of the turntable (by eye) and the centre of the turntable is 430mm (17in) from the scanner for a 'wide' scan. For a close up scan, (macro) this distance should be 265mm (11in).
- Try treating the surface of the object by applying the chalk powder in the powder pen in the accessories box. Alternatively, you could spray paint your object a neutral matt medium grey colour. Pure white may reflect too much light back to the scanner, and black may not reflect enough.
- Ensure that the scanner is parallel with the axis of the turntable. This is easy if the scanner and turntable are on the same surface. If the scanner is mounted on a tripod, check that it and the turntable are level using a spirit level (there may be one built into the tripod).
Step 6: Preparing for a Full Scan
Choose bracket or 360 as the scope of the scan.
- Choose bracket to scan just the surface facing the scanner in detail, or 360 to scan all sides of the object.
- I recommend 12 divisions, which translates to 30 degrees between each scan (360/12=30). For a bracket scan, the scanner will take the current orientation of the object as the central scan, and scan 30 degrees to the left and to the right of that viewpoint.
- You can jog the turntable around to check that the object will not leave the field of view of the scanner while it is rotating. Do this using the innermost left and right arrows in the main toolbar. You can jog a whole division using the outermost left and right arrows.
- You can draw a box around the area of interest in the video preview window if you want to disregard all other areas from the scans. Again ensure you are not cropping off bits of the object as it rotates.
- If you are planning on making multiple scans, such as to piece together an object too large to fit in one scan, you will need to add some markers to aid in reconstruction. I found the best thing for this was some sticky arrows, which you should find in the accessories box. Alternatively, you could use the chalk markers in the box, or features on the object that will always be recognisable.
- You will need three markers for every section to be matched up. If you are doing several whole scans of an object, this will mean just three in total. If you are working your way along a large object, this means three in every transition region of the object (so for a three part scan, 6 markers).
- Attach the markers to your object and ensure they will always be visible to the scanner as the object rotates.
Step 7: Full Scan Your Object
A full scan will probably take 30 - 60 minutes, depending on the scope, resolution and number of divisions you selected. It is a good time to do another job! Just ensure that the scanner and object are not disturbed during scanning. The scanner will only scan solids that are at the turntable, so do not worry about crossing its field of vision.
You can view the scans as they are brought into the computer by clicking them in the bottom library bar. After the final scan is processed the status bar will show the filename again, indicating that the scan is finished. Save your file.
Repeat as necessary for large or complex objects. Your aim should be to have all parts of the object represented between all your scan families. Remember that you will need markers to align these scans later.
Step 8: Attach, Detach, View or Delete Scan Families
Detach your first scan family
- Scan families that are already attached are given green background in the scan library at the bottom of the screen. The software automatically attached the first scan family you made. You can detach this scan family by right clicking its thumbnail in the scan library and choosing 'Detach' from the context menu.
- Right click the thumbnail of your recent scan family in the scan library and choose 'Attach' from the context menu. Scans are labelled alphabetically, so your most recent scan family will always be the one with latest letter alphabetically.
- Bracket or full scans are made up of a series of single scans. You can view these individual scans by double clicking the scan family in the library. The library then shows the individual scans.
- You can view each in detail in the main window by selecting individual scans in the library.
- You can also attach and detach individual scans in the same way that you did with scan families.
- Click the return arrow in the scan library to go back to the top level.
- You may want to delete scans that you don't need in order to save disk space. To do so right click a scan or scan family and choose 'delete' from the context menu.
Step 9: Aligning Multiple Scans
If you have made multiple scan families, such as when scanning a large object in sections, you will need to align these scan families. Click 'align' in the main toolbar. Two geometry view windows are now visible.
Aligning scan families
- If you have not already done so, attach one of your scan families. The software will help you align an unattached scan family with the attached ones.
- Drag the yellow, blue and red dots from the top right of each geometry window to the same respective marker on the object in each window.
- As you drop the dot the view will zoom in. You can then move it again for fine placement.
- When all three dots are in their correct places, click 'align' in the main toolbar.
- The software automatically takes you through
- When the alignment is complete, click 'back' in the main toolbar.
Step 10: Trim Scans
- The scanner will inevitably pick up some geometry of the hardware restraining your object. You can easily delete this.
- Click 'Trim' in the main toolbar.
Select the areas of the mesh to trim. You can do this using the tools in the main toolbar
- Square/circle brush - use these to draw over the geometry to be trimmed
- Draw rectangle - use this to draw a rectangle over the areas to be trimmed
- Draw polygon - ditto for polygons
- All - select all
- +/- - add to or subtract from the selection
- It is very hard to see what has been selected so it is best just to be very careful and sure of what you are doing. You can always undo.
- Click 'trim' in the main toolbar. The selected geometry will disappear from every scan in the scan family. Repeat as necessary.
- Click 'back' when done.
Step 11: Fuse Scans
- Click 'Fuse' in the main toolbar.
- Use the slider in the main toolbar to select a level of resolution for the final mesh. This is given in inches, so you may have to do some conversion to make sense of the numbers. A mesh of 1mm resolution is approx. 0.04". The smaller the number you choose here, the larger your final mesh file will be.
- Click 'fuse' when ready.
- The software creates a new scan family, made up of one final mesh.
- Click 'back'.
Step 12: Polishing, Filling Holes and CAD
One fairly useful feature is fill holes:
- The software scans the mesh looking for holes, and highlights them.
- You can then select which ones you would like to fill by using the brush tools (as for trimming)
- Then click 'Fill holes'.
- The software will attempt fill in the mesh at the holes, with varying success.
- When complete, click 'back' in the main toolbar.
Filling using other software/cloud service
ScanStudio isn't all that great at filling holes to be honest so I'd recommend using the Poisson reconstruction filter in Meshlab to rebuild a completely closed mesh. Another option is to take advantage of Netfabb's cloud STL fixing service, and send it to them using this online form. They'll send you back a well fixed mesh (in my experience) remarkably quickly.
Step 13: Output
- Click 'output' on the main toolbar.
- Click STL or OBJ to save to those filetypes resepectively. STL is the more common, however OBJ is supposed to bring with it the photo textures. I have yet to work out how to ensure this however.
- You will be given a save dialog to choose a name and location for the exported file. UPDATE: ensure that you check the box to export only your green attached mesh (make sure your fused mesh is the only attached mesh before exporting)- otherwise Scan Studio will export all meshes superimposed on top of each other. I've no idea why anyone would want to do that!
- Save your NextEngine scan file (.scn) before closing, in case you need to come back to it. All the scans are referenced from the one file.
Roy Shearer, Nov. 2012