RUG/Pennsylvania/State College/3D scanning

From RepRap
Revision as of 13:36, 29 November 2013 by Jjb5476 (talk | contribs)
Jump to: navigation, search
NextEngine 3D Scanner

Current Progress

Penn State RUG is currently using the Next Engine 3D scanner to replicate and print objects. The intial scanning process is relatively simple, aligning point data and creating a water tight model is a tedious task. The NextEngine Scanstudio software has successfully produced printable files and other software exists that makes turning the scan into a clean printable model. Penn State RUG currently uses Netfabb and Blender to clean, touch-up and ready a scanned model for printing.

Coming Soon

When to scan

Scanning is good for replicating objects that are already made. The Scanner used Penn State RUG is the Nextengine laser scanner. There are some negatives to the laser scanner that need to be taken into consideration when choosing if the object will scan well.

Surface Finish

Laser scanners have problems scanning objects that have a shiny surface since the light is reflected. Laser scanners also have a problem scanning objects that are darker, since the most of the light is absorbed. A way to correct this is to apply talcum power to surface using the brush supplied with the next engine. If the powder is not stick apply hair spray to model before talcum powder. If powder does not work then a light colored matte paint can be applied to surface of the model. Be careful not apply too much paint so that features are obscured.

Geometry

Laser scanners will ignore features that are not visible from the surface, like hollow shapes. They also have issues with undercut angles, since there is no way for the lasers or camera the reach behind the face of the object. To reach hidden faces try repositioning the model and scanning again.

How to scan objects

ScanStudio HD interface
ScanStudio HD Scan Mode

Place your object on the stand in front of the scanner. Using the image on the right side of the scan mode, center your part in the frame.

1. Choose Positioning of scan, the three positions are 360, bracket and single. A 360 scan takes a 360 degree scan of the object. Bracket takes three scan separated by the user inputted angle. Single scan takes a single scan in it's current position.

2. Choose the number of divisions. The division changes the the angle between each scan, in 360 scans the number of divisions is the number of scans it will take to complete the 360 scan. If 4 divisions are chosen the angle between each scan will be 25 degrees. For a bracket scan the division changes the angle between each scan. To find the angle between each scan divide the division number from 360. The divisions slider is not used for single scans.

3. Choose the density of each scan. The higher the density the more data points per square inch. The data points that are taken means more detail but also a larger file size and longer scan time.

Optional Choose your target. This is used to tell the scanner if the piece is a light, neutral or dark.

4. Choose the range of the scan. There are two main modes used by Penn State RUG, macro and wide. Optimal Distance from scanner for macro is 6.5 inches and 17 inches for Wide. You may need to recenter your part in the frame on the right side.

At the bottom of the scan window there are bars that will show the time and memory estimate for the scan.


Aligning, Trimming and Fusing scans

Head model before being trimmed
Head model after being trimmed
"Head model before being aligned
Head Model after being aligned
Head Model after being aligned

Aligning: Aligning the scans will turn many different scans into one model.

1. To start aligning you scans click the align button at the top of the ScanStudio main page.

2. To align the scans start by placing the red dot on either of the images. Then place the other red dot on in same spot on the image. The better the precision the better the the better the final product will be, so pick a prominent feature.

Note It may be help full to mark the image before scanning for easy alignment.

3. Continue to place the blue and yellow dots just like the red dot in step 2.

Note Three dots is the minimum needed to align the scan but more dots can help with better precision

4. When all the dots are placed hit the align button at the top of the window and Scanstudio will align do the rest of the work.

Trimming: Trimming the model will allow for removal of any extra data that is not needed. There are six main tools that can be used to trim the model. These can be seen at the top of the trim page.

Pointer: The pointer can be used to move your model without fear of accidentally selecting necessary data from your model

Circle: The circle allows for the a circular patch of data to be selected for removal. To use it click and hold the left mouse button and highlight the data that needs to be removed.

Square: The square is the same as the circle but selects a square patch of data.

Square line selector: The tool allows you to select large area for removal. It works by creating a box around the data that is going to be removed. Click on one part and move the mouse the other side, creating a square with you two data points being the on a diagonal from each other.

Lasso: The lasso allows you to select large areas of data to be removed. Clicking on a spot on the screen allows you to create a line by connecting a group of lines together all the data points enclosed will be selected for removal.

All: Selecting all with select all data for removal

1. To start trimming your model click the trim button at the top of the ScanStudio main page

2. Choose your trimming tool from the tabs at the top of the page.

3. Hold down the right click button and highlight the data that needs to be erased.

Warning Be Careful to select only data that needs to be erased

Note You can choose either select data or deselect by choosing the plus of minus button

4. When all data is selected click the trim button at the top and let the computer remove those data points.

Fusing Fusing the model will turn a family of scans into a watertight model that can be printed

To fuse the family of scans together click the fuse button at the to of the main ScanStudio page. Choose the level of tolerance for the scan and click fuse.


Making Scans printable

To make a watertight model printable their are different methods that can be used. The three main methods used by Penn State RUG are ScanStudio Polish Tools, Netfabb, and Blender.

ScanStudio Polish Tools

Fill: The fill tool allows for holes in the finished model to fix.

Buff: The buff tool smooths the surface of the scan.

Simplify: The Simplify tool will simplify the mesh and lower the total file size.

Netfabb

Netfabb is also used to make a flat bottom for printing and fixing mesh issues for slic3r.

Blender

Blender can be used to add details that where lost during the scan process.

Extras

Pictures

Statue of Poseidon Scan of statue of Poseidon Printed Model of Poseidon statue Orginal part and final model

Links