'Using Rhinoceros' Discussion Thread

[Willja67]

Thanks Steve for the help. Now for more questions. As you rhino users well know when rhino unrolls something it makes the unrolled portion into a surface as well. I only want the outline of the unrolled piece. Is there a way to get rid of the surface and leave the outline?

There is a shaded ball on the tool bar that if you just click gives a shaded view of the current viewport. If you hold down the mouse button instead of clicking you'll get a set of buttons including one that looks like a camera to take a screenshot of the current viewport.

So how do you do screen grabs when not using Rhino?

 

[rowiac]

So how do you do screen grabs when not using Rhino?

You can do a screen grab in any Windows application by hitting Alt-PrintScrn on your keyboard. This copies the active window to the clipboard. Ctrl-PrintScrn copies the entire screen to the clipboard.

Open up an image editing application (even Microsoft Paint will work), create a new file and paste the clipboard contents into the new file (Ctrl-V) and there you have it. Then save in whatever format you like-- JPG, etc.

Roger

 

[wunwinglow]

I'd rather export the surface (select it so it goes yellow), as an ai file. Make sure you are in a view loking straight down on the surface. You don't have to 'fill the view' as an ai file is a vector format and it will be exported in real dimensions ( you have some control exactly how the export happens). Once you have the ai file, import it into your vector drawing package (still real size, remember) delete any lines you don't need (isolines for example), then you can close, fill, copy, whatever, just like any other vector shape. This will work in Coreldraw, Illustrator, maybe even TurboCAD ( haven't tried it but I understand it imports ai data)

This way you are not crippled by the dreaded 'jaggies'. I can't see the point of going to all the trouble to make a razor-sharp set of surfaces, and then fill your harddrive with massive bitmap files, that look awful if you zoom in.

If you really MUST use bitmaps, wait until you have done all the construction, copies, tabs, layout etc. THEN generate a bitmap for all your fuzzy camouflage and rust stains.

Hope this helps,

Tim P

 

[Willja67]

I've got one thing to say about Rhino:

I LOVE IT!! :lol:

I haven't been this excited about my model in a long time. The learning curve is still a bit steep but I've almost completely redesigned a piece of fuselage in less than 2 hours work that would have taken me ten times as long to do by hand :!:

I've been generally pleased with Rhino except for a few small gripes but I take them all back now that I see what it truly can do( and how easy it is :idea: ).

 

[Gil]

Willja,

I'll second Tim, save it as an .ai file.

To rid the isocurves go up to the circular rainbow icon on top, the object properties box, and left click. The dialogue box will open and down toward the bottom is a checkbox "show surface isocurve". Uncheck the box and the isocurve display and printing will be suppressed.

-Gil

 

[wunwinglow]

Hey, thanks Gil, never realised you could do that. See, you never stop learning!

And yes, Rhino is just excellent! The more you use it the better it gets!

I think I'll stop right there....

Tim P

 

[SteveM]

Thanks Steve for the help. Now for more questions. As you rhino users well know when rhino unrolls something it makes the unrolled portion into a surface as well. I only want the outline of the unrolled piece. Is there a way to get rid of the surface and leave the outline?

Select the surface. Now go to "Curve -> from objects -> duplicate boundary".

Steve

 

[Willja67]

Thanks agin Steve and Gil and Tim for all the tips.

I've run into a slight problem that I'm not sure I'm responsible for.

After I unrolled some of the surfaces I had some pieces that had to be added one on each side so I put one side on and mirrored it. The mirrored piece didn't fit exactly on the other side, obviously something isn't straight somewhere. When I rotated all the cross sections around from the work surface and assembled the 3d model I used ortho for everything thinking that would keep everything lined up. So was that a false assumption or did I mess up some other way?

 

[Gil]

Check, check and re-check..., 3D graphics is full of gotchas. It seems some of the parts have lost their center reference. Go back and check the affected items. Orthographic only affects the viewport and has no effect on 3D precision. One last point, some of the errors contained in the object file can be very subtle until examined at high magnification and even then can be easily missed. I love the transform> 2 Point & 3 Point position commands. They make pasting the bulkheads to the keel a real piece of cake. Also make sure that your keel reference is on the Construction Plane. All sorts of bad things happen when this in not the case.

-Gil

 

[SteveM]

Thanks agin Steve and Gil and Tim for all the tips.

I've run into a slight problem that I'm not sure I'm responsible for.

After I unrolled some of the surfaces I had some pieces that had to be added one on each side so I put one side on and mirrored it. The mirrored piece didn't fit exactly on the other side, obviously something isn't straight somewhere. When I rotated all the cross sections around from the work surface and assembled the 3d model I used ortho for everything thinking that would keep everything lined up. So was that a false assumption or did I mess up some other way?

Are your cross sections perfectly symmetrical?

Steve

 

[wunwinglow]

You MUST MUST MUST be ABSOLUTELY sure you are placing points, ends of curves etc EXACTLY where YOU want them. To to this proficiently, you must understand the snap and constraint functions. Best practise is to turn off all the snap functions except ONLY the one you need for that particular location. This includes making sure stuff is on the construction plane, or moved with the Ortho setting on (limits movements along set axes, ie only horizontally, or vertically, or at some angle you can set)

Also trimming lines can get confusing if you have 'Use Apparent Intersections' switched on. With this switched off, your geometry HAS to actually pass through each other for trims and snaps to intersections to work. So if it doesn't work, there is something up with your drawing accuracy!

Don't plough on without sorting out an error. Rhino will produce allsorts of wonderful shapes that look great, but if there is a glitch, things won't 'get better'. They will most certainly get far worse!

Finally, don't bother modelling two identical sides. Make one half, concentrate on getting that accurate, then just mirror the lot when you need to see the whole design. Two mouseclicks.

Hope this helps,

Tim P

 

[Willja67]

The only variable in the last three posts that I haven't accounted for is if the cross sections are symmetrical. I went through and checked everything for being square and placed exactly where I wanted it. All the cross sections were perfectly(near as I can tell) perpendicular to the centerline of the fuselage.

I've tried the list and angle commands to try and find out how things are sitting relative to each other. Are there better way of finding out relevant info of that kind (angle in xy plane etc)?

 

[wunwinglow]

Will, send me the file. I'll have a look at it for you. I know these things can be a bit tricky to spot!

Tim P

 

[wunwinglow]

If you select something, then click on the 'Object Properties' button (rainbow ring) then click on the 'details' button, you will get a whole bunch of stuff listed, depending on what it is you have selected.

Alternatively, hide everything else except the items you want to check, then look along the lot of them in the front view. You might have to zoom in close, but any out of alignment will show.

Or, if you have something you can snap to, an end, intersection, etc, snap the cursor to that and check the coordinates at the botoom left of the screen. If they are all on the same plane, that coordinate will not change from item to item. and if it is supposed to be on a centre plane, it should read zero. Assuming you build the model along a zero axis!!

Tim P

 

[Gil]

One idea that will allow you to look at each of the asymmetrical pieces is to turn on the grid and use the transform> orient> 3 points and lay a copy of each on the snapped Construction Plane Grid. Use the 2 point command to align the pieces to compare. If they aren't the same then something was wrong when they were constructed and the process needs to be done over again. If they are the same then I haven't the faintest clue as to what's wrong..., but let's see whether they're the same or not as a first discovery and then go from there...,

-Gil

 

[Joseph]

:roll: Here I come with stupid questions....
1) Some parts as wingtips will never unroll, as the shape is partly spheric. But in real models, thanks to the relative 'flexibility' of paper, you get the correct shape. Now, how to achieve that in Rhino? Make the part slightly bigger? Model the wingtip as two flat surfaces (upper and lower sides of the wing)?
2) Landing gear...how do you model those rolled cylinders?

 

[Gil]

Joseph,

The wing bottom to the tip can usually be left as is as the lower camber is much less than the wing top camber. For the wing top camber it's necessary to approximate the shape using straight lines. The need for a "dart" cut will be necessary at the highest curvature point of the airfoil and can be eyeballed with fair accuracy. This may take a little "playing around" with it but is fairly straight forward (sorry for the pun). If Tim doesn't do a short showU before I get back from an errand I'll do one...,

-Gil

P.S. How do you like Rhino?

 

[wunwinglow]

Gil, you are right, the Mk 1 eyeball will get you a good answer. You could spend a lot of time calculating these dart cuts, but frankly the accuracy you would need to make them to 'work', as far as Rhino is concerned, would be WAAAAY finer than you could cut with a scalpel, and more to the point, the thickness of the paper, how you rolled it, the relative humidity, the grain direction of the paper, would all have far more significant effects on the outcome.

Rhino is the anwer to an awful lot of questions, but it can't do everything, particularly when it is only one stage in a whole sequence. Sometimes it is quicker, and just as effective, to 'wing' it!

Short answer, a couple of test prints and assemblies. I often fill such images with a fine ( say 1mm) pitch grid, so if I do need to hack and slash, I can trace out the final shape back onto the artwork.

Same applies for the undercarriage. So long as th image is the right length, just do a test print, cut and roll, mark it when you get to the right diameter the unroll and measure. This will be a bit variable too, as it will depend on the diameter of any core wire, how neatly the rolling is done, what sort of glue is used.

Tim P

 

[Gil]

Rhino Made Wing Tips

The following is one way to create wing tips in Rhino.

-Gil

 

[Gil]

Rhino Made Wing Tips 2

(Continued)