Design Tutorial

[murphyaa]

A few people have asked me to write up a tutorial on how I design, so I thought I'd give it a try. I started one many years ago on the FG forum, but kinda lost interest. Hopefully that won't happen this time...

Today's installment is how to prepare the 3-view of the model, using Photoshop.

First step is to pick the 3-view. You want a top, right side, and front view. Any other views are gravy that'll be used later for panel lines.

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The Top view needs to be pointing nose down in order to work in Rhino 3d, so select the top view using the Lasso command...

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...Cut, paste, rotate 180 degrees, then flatten the image.

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Next up is to turn the background into a layer. Double click on the word Background in the layers window, and press enter.

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Then create a new layer,

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and make it the background

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Then go to Image> Adjustments> Invert
Then on the Layers window, set the opacity to 50% (The grey background fades into the background of Rhino) and flatten the image again.

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Make sure to save the file with a new name as a .jpeg


Next installment, importing the 3-view into Rhino.

[bankww2]

Thanks i am looking for the good tutorial for rhino:)

[Inky]

This is great, I can actually understand what you are explaining. I might be able to learn this pretty easily the way you are teaching it. Thank you so very much for taking the time to do this for us.

[murphyaa]

Ok, so it isn't tomorrow yet, but I figured I'd do the next installment anyway.

How to import a 3-view into Rhino

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When Rhino first opens, select "Small Objects-Inches"

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Click inside the Top View window to activate it.

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Go to View> Background Bitmap> Place

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Find the 3-view you prepared in the previous installment and select it

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This part is up to you. I usually select a spot 8 squares left of the green line
and drag to 8 squares to the right of the green line. This makes sure all 3 views are equal size.

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Repeat for all 3 views windows, using the same 3-view (Makes for consistent scaling between the views)

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Now to make sure everything lines up on one common point. Click inside the Top View window again, then go to View> Background Bitmap> Move

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Select a spot on the 3-view that will be common with all 3 views, in this case the extreme nose.

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Turn off ortho, and drag this to the intersection of the red and green lines (you'll probably have to zoom in really close to see it)

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Do the same for all 3 views, using the same spot on each view (top, side and front)

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As a last check, I always draw 2 lines on the extreme bottom of the fuselage to make sure I got everything lined up. (Notice the front has to go down a bit. Just go back to View> Background Bitmap> Move again

Save, giving it a unique name (For this model, I called it RB-45)

[murphyaa]

The next step is to start designing the model. since the 3-view doesn't have section views, make sure to find as many pictures of the subject as you can to be able to grasp the shape of the fuselage.

You also need to decide now how you are going to develop the parts for the model.

I don't use formers, so there won't be any instructions on how to draw them (I don't know how to anyway)

[murphyaa]

Time to start designing, starting with the fuselage

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Open up the 3-view again, and make sure there aren't any extra lines on it. (I dunno what happened to mine, it didn't look like this when it left Photoshop)

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Based on the 3-view, and a few images, the fuselage is a simple round tube. So begin by selecting the circle with 2 points, and draw several circles at points along the fuselage when ever it changes sizes, starting at the top and ending at the bottom of the fuselage.

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Once you're satisfied that you've got the general shape of the fuselage covered, time to fill it in. Go to surface> loft

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Select 2 circles that are next to each other and press enter. Make sure the seam is on the bottom.

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In the little dialog box, make sure "Rebuild with XX Control points" is selected, and set to 50. the more control points, the closer to the actual shape you want it will be.
Notice you can't really see what you just drew...

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Click in the Perspective window and click in it
Then go to View> Shaded to take care of that

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Continue lofting, making sure to select surface edge (It automatically lines up the seams, saving some work)

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Almost done with the fuselage

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Normally, fuselage noses come to a point and you can just keep lofting. But this particular plane has a rounded nose. This leads to the difficult decision to use petals.(Sorry guys) Start off by selecting arc, and clicking on the top and bottom of the last circle of the fuselage...

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Then pull out to a rounded arc

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Next up is to select the arc, type "revolve" in the command line, and press enter/ Then click the center of the arc, and the center of the circle (make sure the center snap is turned on) move the arc around 360 degrees until you get a half sphere.

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Draw a line starting at the center of the half sphere, and extending strait up beyond it. Then go to transform> Array> Polar, pick the center of the sphere again and type in an even number, in this case I used 10.

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Select all 10 lines, then go to curve> curve from objects> project.

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From the front view, select the sphere to project onto.

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And you get this (This is also how you do panel lines, but more on that later)

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Now, select the nose piece, and click the "Split" button

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Select the projected lines, and press enter

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And you have petals!

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The fuselage is finished. Next up is the Canopy, wings, engines, tails and landing gear. Then panel lines.

[legion]

Aaron, if you save the image as a .png, you won't get the artifacts/blurring. And the actual size of the blueprint is also a factor in how detailed it shows in Rhino. Sometimes it is better to have several images (one for each view) then one large one.

[bankww2]

wait to see wings and canopy

[Pat_craft]

Many thanks for this tutorial ! I will use it for Sketchup.

[murphyaa]

Aaron, if you save the image as a .png, you won't get the artifacts/blurring. And the actual size of the blueprint is also a factor in how detailed it shows in Rhino. Sometimes it is better to have several images (one for each view) then one large one.

Usually I don't have any problems with 3-views. I dunno what happened with this one. I started using one image for every view because it was a lot faster than trying to line up and make sure 3 different images were the same size and scale. When I used 3 separate images, it'd take me an hour or 3 of work making sure each one was the same scale and lined up properly. Now I can drop a 3-view in in about 5 minutes.

And I picked 8 squares because it gives a reasonable amount of detail without overloading my dinosaur of a computer.

[murphyaa]

Many thanks for this tutorial ! I will use it for Sketchup.

I'm not sure how well it'll work for Sketchup. It took me 5 whole minutes to get lost in Sketchup.

[Pat_craft]

I am interrested by the general strategy to modelise your plane. I will try to translate it for sketchup.

[murphyaa]

One thing to check before you get started is the size of the 3-view you're gonna use.

Every time I started to work on the model to continue the tutorial, Rhino and my computer would choke up and freeze. It wasn't until I checked the 3-view and realized it was 8 mb, or 9000px by 9000px that I found the problem. Just loading the background bitmap was eating up all my memory. Once I shrunk it down to a more manageable size (Less than 1 mb), everything works fine now.

[murphyaa]

Stop...Canopy Time!

Time to design the canopy, which can be both a nightmare and a delight. A well drawn canopy makes the model. But it's the hardest part to get right.

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Start of by determining the shape of the canopy. In this case, a simple ellipse.
Select the Ellipse from 2 points tool, and try to outline the canopy.

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Next, select the ellipse, and press the project button.
From the top view, click on any sections of fuselage covered by the ellipse, then press enter.

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And you get this. We only want the one on top though, so we're gonna kill 2 birds with one stone...

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Select all the pieces of the Fuselage, then right click on Layer 1 in the layers window. Select "Change Object Layer"
After that, I usually change the color of the layer to black, for ease of visibility.

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Click the lightbulb next to layer one, and the fuselage disappears.

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Select the unwanted lines and delete.

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This part is tricky. What I do is use a polyline to trace the outline of the canopy trying to balance accuracy of shape, and number of segments.

Then, draw connecting lines across the footprint

Next, draw a line from the middle of the connecting lines to the outline.

Then using an ellipse from center, click on the ends of the connecting line, and the outline.

Repeat for each segment, and hopefully it'll look like this.

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Now, to get rid of the extra bits of the ellipses.

Select the footprint ellipse, and press the Trim button.

Click the sections of ellipses below the footprint.

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And it should look like this

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Now we need to break up the lines into segments. Start by selecting the footprint ellipse. Then press the Split button. Select the profile curves and press enter.

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Now it's split. Do the same for all the rest of the ellipses.

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Now to draw the parts. Go to Surface> Sweep 2 rails

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Click the top line first. The first line picked HAS to be straight for this to work

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Then click the bottom line, and the sides

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Then press enter. In the dialogue box, Click OK with out making changes.

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Rinse and repeat for the rest of the curves.

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Now, to save some work for the other side of the canopy, we're gonna mirror.
Type "Mirror" in the command bar, and select all the canopy sections.
From the front view, click in the middle, and move the mouse. You should now have a mirror of the canopy.

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This next step isn't necessary, but I do it to save time later. We're gonna merge both sides of the canopy into one piece.
Go to Surface> Surface edit tools> Merge.

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Click on two pieces of the canopy that are next to each other.

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Repeat for each section.

And the canopy is done.

[murphyaa]

Hmm. 20 image limit for posts. Now I know. Here's the last shot I wanted for the canopy, showing it on the fuselage.

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[Sidewinder81777]

wonderful thread, I am following with extreme interest

[murphyaa]

I'm gonna put this on hold while I polish of the Rutan Proteus. That'll but the B-45 as the next model, so I can focus on it 100%.

[bclemens]

This is very helpful! Thank you!

[murphyaa]

Time to feather this flightless bird (add the wings)

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First thing to do is determine the width of the wings (I can't remember the official term for it)
From the top view, draw a line from the leading edge to the trailing edge.

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since this 3-view doesn't have a cross section, we're gonna have to wing it (pause for laughter...or crickets)
Use a combination of the curve tool, and polyline tool to kinda make an airfoil shape.

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Now we need to match the chord (thickness) of the wing. Select the airfoill shape u just drew, and type in "Stretch" Make sure ortho is on.
click on a spot on the bottom, then a spot straight up on the top and drag until it's as tall as the wing, then let go.

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Now click the rotate button, click on the front and back of the airfoil, and rotate the trailing edge down to match the profile of the wing.

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Keep the airfoil selected, and press the project button.
Then select the sections of fuselage it overlaps, and press enter.

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For this.
We're not gonna use these in the design phase, they're the shadow marks for the where the wing goes through the fuselage. It's just easier to draw them now.

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Now to draw the wing. Select the airfoil again, and drag it out until the wing changes angle, about halfway through where the engine will be.


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And loft it (same procedure as when we did the fuselage). Make sure the seam is at the trailing edge, and control points are set to 50.

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Hopefully your wing looks like this

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Gonna cover a couple steps in this one.

-Select the airfoil again (It's still at the end of the wing section we just drew), and drag it out to the end of the wing, until it changes angles again. Make sure you move it down to include the wing droop.
-Use the polyline and curve tools to recreate the wing tip.
-Then use the rotate tool to line it up with the center points of the airfoil, and to include the anhedral.
-Highlight the airfoil shape again, and press the split button. Then select the wingtip shape you just drew.

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The airfoil should be split into a top and bottom. Type loft, then select the bottom part and the wingtip.

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Repeat for the top half of the wing tip.
Then, select both parts of the airfoil and press Ctrl-J to rejoin into one piece.
Now loft the outer wing section.

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Wing's done.

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Make sure to put the wings on their own layer. Makes things less confusing later.

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Repeat the wing procedure for the tail feathers.

All done with the wings. It should glide a lot better now.

[murphyaa]

Time to give this puppy some oomph by adding engines.

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The engine nacelle is done almost exactly like the fuselage, with a twist (literally in this case, they angle downwards and inwards)

Use the circle tool to draw to draw the shapes, then drag them into place.

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Then loft.

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To make the engine and exhaust plates
Go to Surface> Planar Curves

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Select the surface edges of the first and last sections

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Press enter

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And Voila

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Put it on it's own layer.

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Now we're gonna make it fit on the wings. Usually I have engines slide over the wing, but in the case of this model, that wouldn't leave enough engine to be buildable. So, we're gonna cut the wings to butt up against the engine.
Press the trim button and select the engine and press enter.

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Then, turn the engine layer off by clicking on the little light bulb by it. and click on the inside edges of the wings. Now u have the wings trimmed to fit the engines.

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Now that we've severely weakened the wings by breaking them up, we're gonna need to add internal support. What I do is use the rectangle tool to draw a box over the top of the wings, then project from the top onto the wings.
Then turn off the wing layer to show the lines just projected (there will be ones on the top and bottom. simply loft between the lines to form a box. To make it square, rather than setting to 50 control points when lofting, click on "Do Not Simplify"

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Now, we need to mark the fuselage and engines where the wing box will go through them.
Turn the fuselage layer back on.

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Go to Curve> Curve from Objects> Intersection, then select the wing box and fuselage sections that intersect.
do the same for the engine, then mirror the engine, wing box and wing so they match on both sides.

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Voila

Almost done. We just need to draw the landing gear, add panel lines, and unroll everything.

[Swampfox]

I'm really learning a lot about how you designers work........Very interesting and educational.......

Also the a\c you selected is one of my most favorite, my dad use to work on them at Kirtland AFB in Albuquerque in the late '60's early '70's.

Thanks for the excellent thread.

SFX

[murphyaa]

Cool. It's always nice to hear compliments. Keeps me motivated.

Next up it finishing up the engineering as I call it; drawing the landing gear and other hangers on (I think this version has little jet engine pods under the wings, and other sensor type pods on the leading edges.

This part takes a bit longer, because it involves combing the internet for any pictures of these parts as can be found.

[bankww2]

next next next.

[mbauer]

Nice thread Murphyaa!

Very nice insight. Haven't tried Rhino yet, but it looks fairly stright forward!

Thanks for the tutorial!

Mike

[bankww2]

Can't wait to see next steps.

[murphyaa]

I've got this one on hold while I clear up some of the backlog created while I couldn't print. I'm about halfway through.

[JT Fox]

Looking forward to the next instalment. I always learn something new.

Cheers JTF

[bankww2]

Murphyaa keep this up.:confused:

[Ober Freak]

Hiho,

here is my short description to design formers in Rhino.

I'm using the command: "_Offset" or from menu: "Curve" --> "Offset Curve"
http://www.papermodelers.com/forum/attachment.php?attachmentid=128021&stc=1&thumb=1 (http://www.papermodelers.com/forum/attachment.php?attachmentid=128021)

Now select your intersection line.
If you don't want the former right at the end of a part, you need to project a new intersection onto your part first. ;)
http://www.papermodelers.com/forum/attachment.php?attachmentid=128022&stc=1&thumb=1 (http://www.papermodelers.com/forum/attachment.php?attachmentid=128022)

Next step is to point to the inside. The "Distance" in the command line gets your preferred paper thickness, or twice if you wanna do joining tabs, too.
(thickness of 120gsm paper is around 0.125 to 0.15mm, 160gsm is around 0.2mm as an example)
http://www.papermodelers.com/forum/attachment.php?attachmentid=128023&stc=1&thumb=1 (http://www.papermodelers.com/forum/attachment.php?attachmentid=128023)

If you are designing just a half fuselage, you probably need to trim the former lines to the centerline, this is not needed when using full hull intersections.
http://www.papermodelers.com/forum/attachment.php?attachmentid=128024&stc=1&thumb=1 (http://www.papermodelers.com/forum/attachment.php?attachmentid=128024)

Now you got your formers. If you also want longitudinal formers, you have to care for the thicknesses of the formers, which could be skipped mostly on "intersection former only" designs.
http://www.papermodelers.com/forum/attachment.php?attachmentid=128025&stc=1&thumb=1 (http://www.papermodelers.com/forum/attachment.php?attachmentid=128025)

My trimmed and mirrored formers next to the original lines.
http://www.papermodelers.com/forum/attachment.php?attachmentid=128026&stc=1&thumb=1 (http://www.papermodelers.com/forum/attachment.php?attachmentid=128026)

In the same manner you could add tabs to your unrolled parts, by offsetting 2 lines.
http://www.papermodelers.com/forum/attachment.php?attachmentid=128027&stc=1&thumb=1 (http://www.papermodelers.com/forum/attachment.php?attachmentid=128027)

[murphyaa]

Thanks for the lesson in formers Ober Freak.

I'll give it a try next time I need formers.

One thing though, I'm a math challenged product of the american public education system. Any chance you could convert the metric numbers to SAE (Standard American Equivelant)?

I've got the tutorial on hold until I get a better internet connection. I tend to make things up on the fly, and that doesn't work when I can only get online once a week or so. Don't wory, I haven't finished the RB-57 yet. It's tied to the tutorial, and I'll finish it when I finish the tutorial.

[Ober Freak]

1" = 25.4 mm
so divide mm by 25 and you get your inches.
0.2mm -> .008" ; 0.15mm -> .006" ; 0.125mm -> .005"

But I haven't found any conversion from gsm to lb.
Probably you could measure your preferred paper's thickness and add .001" for the glue.

[murphyaa]

Not a pictural way to finish the tutorial, but since I just typed this up to answer another question, I thought I'd put it here:

I use the "Project" command to make panel lines.


Use the view that shows the lines best (top, front, or side), and trace over them using the polyline command,


Select the lines, then type project. When it says "Select objects to project on to", select the surface you want the line to appear on, and press enter.


To unroll, you have 2 options (or 3, depending on your version of Rhino.) Unroll developable surfaces, and Smash.

I usually start with the Unroll command. If that doesn't work, or I get angry and turn green, then I use Smash.

With Unroll, you select the surface you want unrolled, then select any lines on the surface. If all works out, you'll have a flattened surface with all the panel lines in place. Rinse and repeat for every part. (That's why I keep my models simple...you have to unroll every single piece.)

If you have a complex curved survace (double curves), you'll have to Smash it.

Select the object, and type smash. Sometimes it helps to say "Hulk Smash" while doing so. You'll get an option to select natural, U, or V. I don't know enough to explain which one to use, I generally experiment with each one until I get it right. Then select the panel lines you want included on the flattened part, press enter, and hang on for the ride.

After you get everything flattened, sort and organize to your preferred preferences (I try to keep components grouped together; i.e. fuselage, wings, engines, landing gear, etc, and orient them so any rolled parts roll horizontally).

After that comes exporting to your graphics program of choice.

Here's how I export:

once you get everything unrolled and arranged (I try to get everything arranged vertically so it goes with the grain of the paper), select it, then click on: file>export selected

Type in an easy to remember name, select the destination folder, and choose a file type supported by your graphics program, and press enter.


Next will be a menu to pick the export size. What I do is decide how many sections I want to break the fuselage into, and assume a length of 9 inches for each section. Say I want 2 sections, I type in a height of 18 inches. For the width, I pick a size that makes the selected objects fill the screen, with small gaps along the edges.


I use Photoshop. Rhino doesn't export in a format that Photoshop supports, so I had to come up with a workaround: 1: export as a .wmf, 2: Open the .wmf in Inkscape. Save the opened file as a .pdf, 3: Open the new .pdf in Photoshop

You'll probably have to resize a bit in your graphics program to get everything to fit properly.