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getting started with openvsp

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Getting Started with OpenVSP
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
1
Audience and Intent
•
Intended audience
–
•
New user to OpenVSP
What this presentation is
–
Quick reference to rapidly and effectively create your first drawings
•
–
•
Basic features and nice techniques seen in other designs
Quick links to find more in-depth coverage on a topic
•
–
And avoid basic mistakes I initially made!
In teaching myself OpenVSP, I made a lot
of beginner mistakes: objects were
warped, I couldn’t figure out what certain
variables did, things didn’t work as
expected, etc. I was inefficient and
ineffective.
Overview and examples
•
–
Background:
Example: current training material organized by year, not by content
Building on shoulders of giants! Lots of good material already out there!
What this presentation is not
–
Not intended to dictate a technique
–
Not comprehensive nor exhaustive
–
Not designed to teach aircraft concepts or designs
–
Not going into the code and algorithms
–
Not (currently) focused on the analysis tools
•
To get better, I did a detailed review of one
of the high resolution complex models that
others created, reviewed online trainings
and videos, experimented, etc.
Along the way, I took notes and
screenshots … and learned a lot (and am
still learning!). I’m not sharing rocket
science (and a lot is obvious in hindsight),
but hopefully some of my notes can make
it easier for the next person …
Blue skies!
As I come up to speed on those, I may do a “Version 2” of this
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
2
Basics
Navigation and Views
Window pull down menu
• Right mouse key: translate view
• From window pulldown menu, select
number of perspectives to view.
Example [Window  “Four”]
• Left mouse key: rotate view
• <r> : set rotation point w/ left mouse key
Various nodes are highlighted. Select one with
mouse and it becomes the point that you rotate
around when clicking the left mouse. Also centers
image at this point.
• <cntl & shift> Left mouse key: zoom in/out
• <c>: centers image around rotation point
• <f>: fits everything visible onto the screen
• Red frame shows active window;
select window you want to work in
with left mouse key
• Hint: to correctly get dimensions of
something, insert a background
image/photo [Window 
“Background…” ] and superimpose
and resize your design on top of it
View image from:
•
•
•
•
Top
Front
Left
Left iso
<F5>
<F6>
<F7>
<F8>
•
•
•
•
Bottom
Rear
Right
Right iso
<F9>
<F10>
<F11>
<F12>
Hint: the odd keys <F5,F7, …> will basically
rotate you 90deg each time (view from top, left,
bottom, right)
KEY: “< >”: keyboard action
Importing
• [File  Import…]
Pulls in another vehicle to design,
which can then be borrowed from…
e.g., if you like the landing gear, etc…
“[ ]” : Menu pulldown or selection on menu
Shown above:
• Window  “Four” brings up four independent
perspectives.
• The top left view uses a background to show an
image of the target aircraft; this is helpful for
matching drawn aircraft to actual aircraft.
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
3
Reference Image
Hint
• This presentation uses the Cessna 337 for many
examples.
• Available at http://hangar.openvsp.org/vspfiles/286
• Thanks and credit to Brandon Litherland!
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
4
Geometry Browser [Model  Geometry…]
Overview of “Geom Browser” window
Adding Component
• Open [Model  Geometry…]
• Select parent component
• Menu to add, edit, and view structural components
• Select object to add using selection box, then [Add]
• Components, once added, are listed in the window
• Object will be added as Child to the Parent
• “Children” belong to “Parents”. Children are shown
indented to the Parents and preceded by “___^”
Viewing Component(s)
• Select component(s) to view
Selecting Components
• Selecting multiple components is done using <ctrl>
or <shift> as in Windows. “Copy/paste/cut” in Geom
Browser works at component level
• Selecting a Parent selects all Children as well
Hint: Also select structural components in the viewing
window by “Toggling pick mode” <P>. Then select a
component in the viewing window and it will be
selected in Geom Browser
• Selecting [Show Only], [Show], [No Show] will take
the appropriate action on the selected components
• Change how the component is shown using
“Surface” settings
-
“Hidden” – white surface
“Shade” – adjusts based on lighting settings
Hint: “Normal” works for most operations
Geom Browser Window 
Here, “AltProp Parent” (highlighted) is a child of “Fuselage Parent”, and is the
parent of “AltProp” (in bold). Selecting the parent (“AltProp Parent”) automatically
selects the child, as shown here. At this point, you can select Wire, Hidden, Shade,
etc to see these two selected components in different ways
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
5
Making Components – “Gen” Tab
Overview
• Add a component as shown on Geom Browser
-
Many/most things can be built by combining the “Fuselage” and
“Wing” components so this presentation spends most time on
these two components
• Once selected, the component can be modified
-
This presentation is a brief overview of some of the more
common features and settings; not all features are discussed
“Gen” Tab
• Common to most components, this tab allows you to set the
following:
• [Name] : Name the component
• [Color] : Viewing color
• [Tesselation] : Tesselation / fineness of the 3D surface
-
Hint: As reference, the Cessna used 65 for the lift and control surfaces,
and 33 for the non-control surfaces
• [Mass properties] : Used for calculation of W&B
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
6
Making Components – “Xform” Tab
Transforms
Attach to Parent
• Coordinate System (“Coord System”)
• Identifies what action child takes if parent
moves or is rotated.
-
Sets the XYZ location and any rotation.
-
[Rel] is location relative to the Parents origin.
-
[Abs] is location relative to the origin.
-
Hint: Most objects should be set as “Rel”. This way, if a
parent grows or moves, the child moves with it.
Symmetry
• Used to create symmetry in objects. Examples:
- Planar: Left/right struts, landing gear, turbine, etc.
- Axial symmetry: Missile fins, prop blades
• “None” does not move child if parent
moves
• “Comp” moves the child relative to the
parent origin transform (component xform)
• “UW” moves the child relative to the parent
surface. User adjusts the rotation /
translation relative to the UW location
• Hint: All attachments appeared to be with “Comp”
in the Cessna 337 design.
• Select plane/axis around which the symmetry occurs
• “N”: Identify the number of items to be duplicated
• Hint: If the object is built on the axis of symmetry, it won’t be
seen, as it will reflect on itself. To see the symmetric object,
adjust the coordinates to offset it from the axis of symmetry.
 Two booms on the Cessna 337
built using XZ symmetry
See http://openvsp.org/wiki/lib/exe/fetch.php?media=workshopv3:symmattachsubsurf_gary.pdf
for more details on these features
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
7
Making Components – “Sub” Tab
Subsurface
• Very useful for creating “sub-surfaces”; differentiating
between a surface that is co-planar with the main
surface
• Examples:
-
Ailerons and control surfaces on wings
-
Windows and doors on fuselage
-
Access ports and panels
-
Solar cells on aircraft
Shown: A door outline is
added to the Cessna
fuselage using subsurface
feature
Adding Subsurface
• [Type]: Select the shape of the object
• [Name] : Name it
• Select whether this is inside of the airplane (eg, a rib)
or outside (eg window/door)
• Position and size sub-surface with centering and
length dimensions
• [Add] the sub-surface
See http://openvsp.org/wiki/lib/exe/fetch.php?media=workshopv3:symmattachsubsurf_gary.pdf
for more details on these features
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
8
Making Components – “Sub” Tab
Subsurface
• Very useful for creating “sub-surfaces”; differentiating
between a surface that is co-planar with the main
surface
• Examples:
-
Ailerons and control surfaces on wings
-
Windows and doors on fuselage
-
Access ports and panels
-
Solar cells on aircraft
Adding Subsurface
• [Type]: Select the shape of the object
• [Name] : Name it
Shown: Control_Surf subsurface added for aileron.
• Select whether this is inside of the airplane (eg, a rib)
or outside (eg window/door)
• Position and size sub-surface with centering and
length dimensions
• [Add] the sub-surface
See http://openvsp.org/wiki/lib/exe/fetch.php?media=workshopv3:symmattachsubsurf_gary.pdf
for more details on these features
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
9
Making Components – Fuselage “Design” Tab
Overview
• This tab varies depending upon type of component
(eg, Fuselage, Duct, PodMan, etc). These notes
apply to building a fuselage
• Consider “Design” a high-level “summary” of the
component
Design
• [Length]: Set the length of the object
- Hint: Consider using feet or meters as your units. While not
a requirement, three orders of magnitude are used by
default, so working at .001 of an inch doesn’t provide a
huge benefit for most designs
- Hint2: Length of the fuselage (or wing, etc) can often be
found online or in the POH
Design Policy
• [Xsec Order]: Monotonic
- Hint: There are other options (eg, LOOP and FREE), but it
seems Monotonic covered all of the examples that I could
easily find…
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
10
Making Components – Fuselage “Skinning” & “Xsec” Tabs
Overview
• “Skinning” and “Xsec” identify and control major
changes (cross sections) in the wetted area
- Hint: Most aerodynamic designs benefit from a “less is
more” strategy: only a few transitions define major surface
area inflection points. For example, cross sections between
prop area, engine area, cabin area and tail area, since they
could all have significantly different wind exposure.
Some of the major surface area
cross sections for this design
Hint: keep first (cross section “0”) and
last cross sections as POINTs to
make 3D design watertight and
enable analysis tools to best work
More information:
• http://openvsp.org/wiki/lib/exe/fetch.php?media=hahn_modeling_2013.pdf strategies for creating fuselages and shapes
• http://openvsp.org/wiki/lib/exe/fetch.php?media=workshopv3:vsp_skinning_explained_mcdonald.pdf detailed presentation on skinning
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
11
Making Components – Fuselage “Xsec” Tabs
Xsec Cross Section
• [number] – The active cross section
- Note that it is highlighted when looking at the design
- [Insert/Cut/Copy/Paste] works at the cross section level
a
• [Num U] – How fine should the wire mesh be
- Hint: sharper curves benefit from higher numbers
• [XYZ] – Location of the cross section
- There are two numbers: e.g. for X, 0.3660 and 7.25260
- The first number is a percentage of the total design length,
which was set in the “Design” tab; the second is the resulting
actual coordinate. E.g. 19.78320 * 0.36660 = ~7.25260 (with
rounding)
b
b
• [RotXYZ] – Surface rotation in degrees
- E.g., “cross section 6” is rotated here 10 degrees around Y axis
Xsec Type
• [Choose Type] – Select best shape for cross section
- [General_Fuse] (General Fuselage) offers great flexibility
- [Circle] might make more sense for something like prop spinner
- [Point] for first and last cross sections. Needed to make design
watertight
• [Show] – Use to see the shape and effect of changing
the values (eg, height, width, etc)
KEY: “< >”: keyboard action
Split screen view of Skymaster 337 from top and side.
a) Cross section ”6” shown and highlighted
b) [Show] was selected to see how changing Height/width/etc parameters changed
the shape
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
12
Making Components – Fuselage “Skinning” Tab
Skin Cross Section
• [number] – The active cross section
- Active cross section is highlighted (here, #5)
a
Top / Right / Bottom / Left Side
b
a
c
b
c
• Used to control how the side is “skinned”
b• Left numbers control left side of cross section; right side
c controls right side of cross section
• [Set] – Used to specify a value. If not selected, system
chooses “best-fit” value based on adjacent cross sections
• [=] – When selected, left and right sides of cross section
are equal
b
c
• [Angle/Slew] – Degrees between +/- 180
- Hint: Left and right angles are usually the same at a cross
section, since it is usually a smooth transition.
- Example exception: cross section 5 is for the windscreen,
where top surface arrives at 15deg and leaves at 40deg
- Hint: Slew is often 0, unless you want a warped surface
• [T/B Sym] / [L/R Sym] / [All Sym] – Enforces symmetry
between top/bottom, left/right, and all sides (respectively)
when selected
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
13
Making Components – Fuselage “Skinning” Tab
Top / Right / Bottom / Left Side
• [Strength] represents how “long” the angle is held before
attaching to the next cross section. This number can be
from 0 to 1e12
• [Curvature] is another way of controlling the curve
- Hint: Don’t select this. Let the system automatically choose this
value. Much better to use STRENGTH to control the curve.
Strength: In this cartoon example, the angle (45deg) is identical for these five cross
sections, however the strength varies respectively as follows: 1, 2, 3, 5, 10
For more information, visit http://openvsp.org/wiki/lib/exe/fetch.php?media=hahn_modeling_2013.pdf for a nice writeup on strategies for shaping aircraft with OpenVSP.
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
14
Making Components – Wings “Plan” Tab
Total Platform
• Change [Span] and [Chord] to automatically set area.
• Adjusting [Area] will proportionately adjust [Span] and
[Chord].
Tip Treatment
• Change according to the desired tip for the wing.
Root Incidence
• [Incidence] – Adjust angle that the wing is attached to
the aircraft (versus the longitudinal axis)
• [Incidence Loc] - Location along chord that airfoil is
rotated
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
15
Making Components – Wings “Sect” Tab
Overview
• Similar to fuselage, the wing can be broken up into
sections and independently controlled.
- Hint: Sections are created from the centerline to the wing tip
• This is helpful if features change in portions of the wing
(eg, sweep, profile, airfoils, twist, dihedral, etc.)
- Hint: can also be used to generate wing tips, flying wings, etc.
Section Planform
• Select items that are to be specified. Other parameters
are automatically calculated.
- Only certain combinations of control are permitted. Only
one item may be selected in each column. Some
settings may be mutually exclusive.
AR
Aspect ratio
Ave C
Average chord
Span
Wing span
Root C
Root chord
Area
Wing area
Tip C
Tip chord
Taper
Wing taper
Sec SW
Secondary sweep
KEY: “< >”: keyboard action
Wing is broken up into two sections. Dihedral, sweep, section size, and airfoil are all
different for each section in this example.
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
16
Making Components – Wings “Airfoil” Tab
Overview
• Each section of the wing can have its own airfoil
• [Choose Type] - Airfoil can be defined using various conventions 
• Input parameters change based on selected airfoil convention
NACA 4-series used to define Section 1 of airfoil. Based
on T/C, Camber, and location, a 4 series NACA foil is
created.
Hint: [SHOW] can be used to show what the airfoil looks
like with the selected dimensions (shown below)
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
(shown above) Different possible
conventions to define an airfoil.
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
17
Making Components – Wings “Blending” Tab
Overview
• Blending is used to describe how airfoil sections are joined
• Leading edge and trailing edges are independently controlled
• Inboard is towards the fuselage; outboard is towards wing tip
Intersection 1 with the
different edges identified
Inboard
Trailing edge
Outboard
Trailing edge
Inboard
Leading edge
Outboard
Leading edge
Example of wing blending; note the smoothing of transitions.
Image credit: Rob McDonald
KEY: “< >”: keyboard action
• Video tutorial:
https://www.youtube.com/watch?v=bGRYZr7rS94
• Presentation:
http://openvsp.org/wiki/lib/exe/fetch.php?media=workshop17:adv_wing.pdf
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
18
Making Components – Wings “Blending” Tab
Intersection 0 settings. [FREE] match connects two straight
lines.
Intersection 1 settings. [OUT_LE_TRAP] matches the inboard
leading edge – to match the outboard leading edge trapezoid – .
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
[ANGLES] match defines an angle at which they meet (here, 0
deg). Adjust “strength” to lengthen or shorten the initial angle.
Wing section(s) added at end with high dihedral on
last wing section to create wing tip or winglet.
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
19
Geometry Type: PodMan
Overview
• Automated way of adding a person to check sizing
• Added through “Geom Browser”
• Set posture through by adjusting angles of joints (in degrees)
• Note that figure may need to be rotated for design
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
20
Geometry Type: SeatGroup
Overview
• Automated way of adding groups of chairs
• Added through “Geom Browser”
• Control chair size on DESIGN
• Control seat layout on LAYOUT
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
21
Props
Overview
• Depending upon what you want to accomplish, various techniques
can be used to draw props.
- If you wish to draw the actual props, use “Geom Browser  Add Prop”
- If you wish to see the extent of rotation (e.g. if helicopter rotor could hit a tail
prop), then draw using “Geom Browser  Add “Geom Browser  Add
Fuselage”
“Geom Browser 
Add Prop”
“Geom Browser 
Add Fuselage”
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
22
Making Props – Propeller “Design” Tab
ConstructXoC
X/C of construction line
Diameter
Propeller diameter
NumBlade
Number of propeller blades
Beta34
Blade pitch at 3/4 of radius
Rotate
Rotation of first propeller blade
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
23
Making Props – Propeller “Fold” Tab
Angle
Propeller fold angle
(0 and 90 shown)
Image credit:
“Modeling Conforming Folding Propellers – OpenVSP Workshop 2017”
Radial/R Radial position of fold axis
as fraction of radius
(0.2 and 0.8 shown)
Axial/R
Offset/R
Azimuth
Elevation
Axial position of fold axis as fraction of radius
Offset position of fold axis as fraction of radius
Azimuth angle of fold axis direction vector
Elevation angle of fold axis direction vector
KEY: “< >”: keyboard action
“[ ]” : Menu pulldown or selection on menu
“Geom Browser 
Detailed presentation on folding props
http://openvsp.org/wiki/lib/exe/fetch.php?media=workshop17:litherland-folding_blade.pdf
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
24
Other Helpful Hints
Reading VSP2 using VSP3
Insert a cool background and show your vehicle flying! 
• [File  Import…  OpenVSP v2]
Note that there is an algorithm that
changed between VSP2 and VSP3, so
VSP2 designs are often deformed or
missing components when imported
into VSP3
Units
• Rotation is in degrees
• Length units and XYZ positions can
be any units (inches, feet, etc) and
the default is three digits accuracy.
• Hint: many designs are done in feet
and meters, since 1/1000 of an inch
or cm is not practical nor valuable for
most designs.
Other helpful hints
• Internet Explorer seems to work better than Chrome for downloading VSP files
• Save often; its not automatic!
• Don’t close VSP; it will close the OpenVSP GUI if you do
© Michael McDonald
https://www.linkedin.com/in/mcdonaldmichael/
25
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