This exercise uses SketchUp Free1, National Health Survey stature data2,
and link length data3 to create a model that can be used to explore the spatial
relationship between a worker of a given size and a work bench of a given size.
Workplace and worker parameters for this exercise see:
Reach Limits
Bench:
Width: 2m
Depth: 1m
Height: 0.9m
Top thickness: 0.05m
Legs: 0.05m x 0.05m
Worker (5%female stature2 and average body proportions3
Stature: 1.504m
Floor-Shoulder: 1.230m
Distance between shoulders ÷2: 0.194m
Arm+Forearm+Hand: 0.663m
Floor-Hip: 0.797m
Distance between hips ÷2: 0.144m
Location/position:
Facing Bench
Center on long side
Distance away from edge: 0.10m
This exercise uses sketchUp Free -- well because it's free. The basic procedures for creating a model are similar for other CAD programs.
It will be assumed that you are familiar with the basics of Trimble SketchUp Free.
If not, there are a number of excellent on-line tutorials that will help you quickly acquire the necessary skills. SketchUp Fundamentals
SketchUp is rapidly evlolving, so you may find some differences between your desktop and the desktop
used in in the tutorials and this exercise, but the basic steps should be the same.
You also will find significant diffences between the on-line UI and the the desktop UI, but, again the basic steps for creating
the model should be the same.
Open & log into Sketchup Free (you will need to register and set up an account). The free version will be fine for this exercise.
Click to select the human figure in the center of the drawing and press delete.
We will be working in metric units so open the “Model Info” pain using the menu on the right side of the window and select “Format>0.0m” and “Precision>0.000.” (see Fig 1).
Construct the bench top
Select the rectangle drawing tool from the drawing menu on the right side of the window. Notice that:
a little rectangle appears by your cursor after selecting the rectangle tool.
instructions for using the rectangle tool appear in the lower left corner of the desktop window.
Click on the origin (intersection of red, blue and green lines. Notice that the cursor tends to “snap” to the origin as it gets close.
You will notice this as the cursor seems to be drawn to all intersections of lines if you move the cursor close to an intersection.
This snap feature facilites clicking on your desired target.
Now move the cursor away from the origin in the red-green plane. Notice that:
a rectangle is formed as you move away for the origin.
the rectangle will be blue as long as you are moving in the red-green plan.
the distances along the red and green axes are show in the measurement box in the lower right-hand corner of the window (see fig 2)
You can adjust the position of the cursor until you see 2,1 in the measurement box or you can just type "2,1"
If you just type "2,1," a 2.0x1.0m rectangle will be created.
You now have a perfect shadow of the workbench.
Give the bench top some thickness.
Tip: A 3-button mouse is very helpful.
Select the pan tool from the vertical menu bar on the left.
Hold the left mouse button down and move the mouse to "pan"
Use the scroll wheel to "zoom"
Hold the left mouse button + the scroll wheen down to "orbit"
Select the push-pull tool from the drawing menu on the right side of the window (you will see
a "push-pull" symbol by the cursor and instructions for using the push-pull tool in the lower left-hand corner of the SketchUp window).
Click on the bench surface and move the push-pull tool upward in the direction of the blue axis. Notice that:
As you move, the rectangle is extruded into the third dimension
A line forms between your starting point and present position. It should blue – meaning that you are moving in the blue direction.
The measurement box shows how far you have moved.
Move until you see the desired bench top thickness,0.05, in the dimension box or use the short cut and simply type .05
You now have a bench top lying on the floor.
Tip: After you have completed each object, you should make it a group to prevent accidently changing its shape or size. To do this:
Select the cursor tool
Click well above and to the left of the box.
Hold the left mouse button down and move down and right to draw a box around the top.
You will notice a color and texture change in the selected objects.
Now position your cursor over the selected object and press the right mouse button.
A drop-down menu will appear. Select “make group.”
Comment: you also will see another menu item called “make component,” which also, can be used to preserve the geometer of your model.
Components have more functionality than groups and are slightly more complicated. We will discuss components in a later lesson
Move bench top to desired height.
The instructions are to create a workbench 0.9m high – not the present 0.05 meters. Use the move tool to move the bench top to the desired height
Click on the bench top to select it . Comment, since you have made it a group, just clicking on part of it will select it – you don’t need to draw a box around it.
Get the move tool form the menu on the left side of the screen.
Click on the bench top and move your cursor parallel to the blue axis. You will see:
A line between your starting point the cursor. The color will correspond to the axis along which you are moving. You want to move the top upward parallel to the red-green plan. The line should be blue
You can move the top to the desired distance shown in the measurement box or you can just type the distance. Since the top is already 0.05m above the floor, you should move 0.85m along the blue axis.
Hint: You can click anywhere on the object to move it, but it will minimize confusion if you click on a conspicuous well isolated edge or corner.
You now have a bench top This would be a good time to save your drawing file if you have not done so.
Construct bench legs:
To construct the legs, you may need to use the “orbit” and maybe along with the zoom and pan tools to get a good view of the corners on the bottom of the benchtop.
Get the rectangle tool
Select a corner on the bottom of the bench
Move your cursor parallel to the red-green plan (The rectangke will be blue as long as your curson is in the red-green plane.)
You can move the cursor until you see 0.05, 0.05 in the measurement window your you can simply type .05,.05.
Hint, it will help you to see what you are doing if after clicking on the corner you make a large rectangle and
confirm that the rectangle is blue and then type in the dimensions rather than making a small box that approximates the desired size.
Use the push-pull tool to extrude the rectangle down 0.85m. You can do this by observing the distance in the measurement window, moving in the blue direction and then typing .85 or by inference. Inference is a shortcut in which you extrude the rectangle down and then click on a reference point – in this case the origin of the red-green-blue axes.
Select the cursor tool
Draw a box around the leg
Right click on the leg
Click on “make group” from the drop-down menu
You can now repeat this for the other three legs or use the copy move tool.
Copy and move legs to other 3 corners
Select leg
Get move tool.
Press option button (on Mac) – notice a small "+" sign next to cursor.
Click and release left mouse button to select upper corner of leg the corresponds to desired lower corner of bench top
Move cursor to desired corner. Notice that
a second leg appears and moves in the direction of your cursor
the cursor will snap on the corner as you get close.
Click on corner of bench
Reposition the bench top as necessary and repeat for remaining legs.
Make legs a group
Make legs and top a group and assign and tag them
Click on the tag menu item on the right side of the window to open the tag window.
Click on "+" to creat a new tag a tag & name it “Bench 2x1x0.9”
Click on the "entity info" menu item on the right side of the window to open the “model entity” window or
right click on your group and select "Enity Info" from the dropdown menu"
Click on "Untagged" and a "Choose Tag" Window should appear. Select the tag you just created to assign bench to tag layer
Experiment with hiding and unhiding the bench by clicking on the "eye" icon in the tag window.
a
b
c
d
e
f
Figure 1 Workbench construction: Use of a) "rectangle" tool to create bench surface in the red-green plane;
b) "push-pull" tool to give bench top thickness;
c) "Move" tool to move bench top to desried height (after grouping);
d) "rectangle" tool to create cross secion of leg on underside of bench; use "pan," "zoom," and "orbit tools"to position bench
e) "push-pull" tool to extend leg from bottom of bench to origin;
f) "copy-move" create other 3 legs (fater grouping the first).
The entire bench sould then be grouped and tagged.
Warning:
Always create your drawing objects as untagged and then group them and then tag them.
The tags give you the ability to hide the parts of the model with a given tag, but they are still in your model.
Failing to group objects before taggin the can result in un-intended interactions between
your tagged objects that you've hidden and your current drawing -- and a lot of frustration.
You will see a pencile icon by each tag. Clicking this tag will associate all of your drawing and drawing edits with this tag.
For now, you should construct all of your drawings as "untagged"
Construct stick figure and touch reach limits for a worker with 5%female stature2 and average body proportions3
Locate worker:
Get the tape measure tool (tool menu on left).
Click on the green axis (not the origin) & move your cursor parallel to the red axis.
You should see a red line appear between the point where you clicked on the axis and
the cursor indicating that your cursor is in the red-green plane.
You also should see a dashed line parallel to the gree axis in the red-green plan.
This is a guideline and it is used to create reference lines and points for constructing a model, but they are not part of the model.
Use tape measure tool to create a guideline 0.1m from red axis in red-green plane. This guideline should be outside the shawdow of the benchtop
The worker will be constructed at the intersection of the two guidlines.
Construct the torso:
Body: Use line tool to construct a 1.504m line from the intersection of the guidelines line parallel blue axis to represent a 5% female.
Midpoint between shoulders: Use the tap measure tool to locate a point 1.230m from the intersection of the guidelines on the line you just constructed.
Shoulder: Use the line tool to make a line parallel to the red axis 0.194m long
Opposite shoulder: Use the
Hip:
Leg:
Opposite hip:
Opposite leg:
Tip: You may choose to keep the line between the legs. Although it might look strange, it provides a useful reference point if you move your worker around
Make worker a group
Construct the arms and reach limits/envelopes
Use "line" tool to construct right arm
Use "circle" tool to make a circle about the shoulder (red axis a circle around the shoulder with radius equal to arm length"
Hint: The color of the circle indicates the orinetation of the circle.
use the the arrow keys to change the orientation
Use the "circle" tool to construct a temporary path circle about the fingertips and perpendicular to the arm.
(this will needed temporarily for the following "folow-me" tool. It will then be erased.)
Bisect the circle parallel to the blue axis.
Truncate the area behind the worker outside of normal reach limits.
Use “follow me” tool to rotate semicircle and make hemisphere.
Construct circle about fingertip perpendicular to arm.
Select circle that form path.
Select “follow me” tool.
Click on semicircle.
Cleanup hemisphere.
Make arm and hemisphere and group.
Use copy-move tool to create left are and hemisphere.
Make a group.
Create a tag “5% Female.”
Select entity into
Assign the stick figure to a “5% Female” tag.
Hide the 5% female model.
Construct stick figure and touch reach limits for a worker with 95%male stature2 and average body proportions3
a
b
c
d
e
f
g
Figure 1 Worker construction: Use of a) "tap measure" tool to create point in red-green plane where worker is to stand;
b) "line" tool to create stick figure & then group;
c) "Line" tool to construct outstretched arm; "circle" tool to make a circle about the shoulder (red axis);
d) "circle" tool to create a path circle about the finger tip (gree axis); "line" tool to bisect circle about shoulder; "erase" tool to remove perimeter behind torso;
e) "follow me" tool to creat hemisphere (select path circle, then select too, then click on semicircle above or below arm )
f) erase tool" tool to ;
g) "copy-move" to create second arm and hemisphere about left shoulder.
The entire bench sould then be grouped and tagged.
Your model of the small and large workers and the workbench is a very power tool for evaluating the and designing workstations.
This model will enable you to determine with a high degree of accuracy if most workers will be able to reach a given work objec without bending or twisting.
It will enable you to concisely specify where to locate a work object on the bench to reach an object or in some cases avoid touching work object.
You can construct work objects and construct a virtual workplace and be confident that most workers will be able to use them.
you can use a virtual work space to deterine reach and move distances and comput normal work times use MODAPTS5 or other predtermined time systems.
Turn tags on and off to compare reach limits for large and small workers.
Here are some tools to explore that will help you explore your workstation model.
Use "Orbit," "zoom," and "Pan" tools to comare reach limits on workbench.
Use the Views tool and window (right menu column) to quickly change from side top, from, isometric, etc. Views
SketchUp provides "perspective" and "parallel" ortho views. In the perspective view, object size decreases with distance.
a
b
Figure 3 Model View Window enables the user to quickly switch among orthogonal and isometric views, a.
The buttons in the upper left corner of the view window switch the ortho views between "parallel," a, and "perspective" views, b.
These view are very useful for getting screen shots of standad views for a report.
It is not possible to insert a dynamic digital model in to a written report.
The convention is to show the model as two or three orthogonal views and to maybe include an isometic view as well. (see Figure 4).
These views should be "parallel" views -- not perspective views
SketchUp Free does not provide a way to show automatically show three orthogonal views.
SketchUp Pro provides a companion program "Layout" that cab be used to generate and arrange desired views. This is a common featurein other programs.
SketchUp Free can be used to show orthogonal views, which can be captured as screenshots and then arranged int table or picture editing tool.
Figure 4 Workbench construction: Standard views of 5%tile female with finger touch limits facing bench.
Notice how top view is aligned with back view and back view is aligned with side view. Also, notice that all are
"parallel" views -- not "perspective" views.
Dimensioning:
Sketchup provides a simple dimensioning tool located in the vertical tool menu bar on the left of the drawing windo.
Select the dimension tool and the snap on two corners in your drawing. The curso will tend to snap on the corner as you get close.
A line will form between the two points and the distance between the two points will be displayed.
Move the cursor away from the model and release the mouse button when you get to the desired distance.
SketchUp Free gives you a limited number of dimension formating options in the model info window in the lower left (see Figure 3).
These must be selected before creating the dimensions.
Section Tool:
As the name suggests, the section tool enables you to take cross-sections of your model and see what is inside.
Select the "section"tool from the left tool menu. (its in the same popup as the dimension tool).
Click on a reference point such as the origin or a corner of your model. You will need to select the desired orientation of the section plane.
Like the circle tool, the section plan will be blue when it is parallel to the blue axis (parallel to the red-green plane).
Use the arrow keys to select the desired orientation.
If you selected the origin and specified a section plane parallel to the red-green plane, all of your model above the red-green plane will disappear.
You can use the the move tool to move the section plane up and down as desired.
The section plane is a useful tool for detemining the reach limits on the surface of the bench (see Fig)
Figure 5 Section tool: The section tool can be moved through a drawing in any direction to view what's inside.
Materials Window
The materials window (left vertical menu bar) provides a limited selection colors and tectures
SketchUp Pro provides a more extensive set of colors and tectures.
Scale Tool
Use the "Scale" tool to scale all or parts of your model
Example: Copy and scale your worker to another percentile stature
Example: Copy your bench and use the scale tool to change the length fo the legs
Multiple copies tool
You've already seen how to copy and move part of a model by pressing the "option" key after selecting the move key, but before moving the desired object.
Follow this by typing "*" and an integer automatically repeat it that number of times
Try making a row or array of work benches.
components
Components are like groups, but they have many more features
you create a component in the same way that you create a group.
Select the parts of the model you want to make a group and selected "Make Component." You will be asked if you want to specify an insertion point and name.
You also have the option to export a component to an external file or library so that you can import it into another model
Find the components window in the left vertical tool bar.
SketchUp 3-D Warehouse
The 3-D warehouse provides an extensive library of Models created by others that can be inported into your model
Find a "Search 3D Warehouse" window in the components window.
Figure 5a shows an example of a hospital bed that was imported from the 3D Warehouse into the model we created.
Try searching and importing a model of interest to you -- Hint: Use the "explode tool" (right click drop down menu) to ungrup the imported modes as needed
Figure 5b shows the hospital bed with the 5%Female stature. It can be seen how she would have to bend to reach the bed or a patient lying on the bed.
Figure 5 3D Warehous: the component menu was used to search for a hospital bed that was then imported into the model, a.
The view button for the 5%tile female was then selected to superimpose the worker and reach limits on the bed, b.