Software for Design

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Rienk, Jul 27, 2010.

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1. Jul 27, 2010

Rienk

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In several threads, an indirect topic of software files came up; so it brings up the question:

What software do the professionals (or at least serious amateurs) here use for designing aircraft? I see that Orion has posted a Rhino file, others have mentioned Solidworks... who else uses those, and what else is used?

Those two are obviously 3D programs,. but I don't know what other features they provide (FEA, or?). I have friends whose companies use Catia, but that's pretty pricey per seat. On the other end of the spectrum, some friends have designed several planes using basic spreadsheets and Cadkey.

What is/are your weapons of choice?
Inquiring minds want to know!

2. Jul 27, 2010

Autodidact

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Big thread on this a few months ago, a search will yield much of interest. Keyword "software" I think, others will remember this thread and might give you a better keyword.

Here we go, "What software do you use?" - in the design/technology section.

3. Jul 28, 2010

Monty

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My weapon of choice depends on how big and dangerous the prey is.:gig:

Seriously, this is the ONE subject I can speak authoritatively on. I am old enough to know what a scum bag is. I have used an electric eraser:roll:. I am young enough that when I was a kid, the first cad system I used was one I wrote myself on a Tandy 1000...it sucked.

Later on I moved to AutoCad. Then there was the silverscreen episode I'd rather forget. Then I got into the big leagues with Unigraphics. I've used Solid Edge, Solid Works, and used to torment the Pro E sales people. I've been using Rhino since version 1 or before....can't remember if I tried the development version or not. Then there was a brief stint of Alias. And I've tried quite a few of the low end packages out of curiosity. On the FEA end of things, I've used everything from hand written Fortran code to ANSYS. I've also used quite a few CAM packages. So I have a pretty good feel for the landscape. I can usually pick up a software package and be doing something useful in about 30 min.

Things have changed a lot over the years. you used to have to buy a $30K SGI box just to play. Now thanks to the gamers, you can get a rockin' box for$1500. FEA Analysis you might need to spend a bit more, but not much.

The CAD world is divided into 3 tiers. At the top are packages like Unigraphics, and Catia. A full blown seat of either of these can do anything you want. You can do free form parametric, analysis and 5 axis cam, sheet metal, you name it. you can build an airliner or an entire car, and coordinate between various organizations, while keeping track of revisions. They are enterprise level solutions and you will pay dearly for the capability. In other words forget it, cubic .
Pro E would like to play here...but..HA HA HA.

Then there is the mid tier. Solid Works is the leader. Solid works is a really good package. It has become a kind of industry standard. Does most things well. Free form tools are not going to be as good as the big boys. Parametric. Falls in the less than $10K price range. Also Solid Edge Pro E etc. Then there is where we can afford to play. The$5K or less range.

First you have to understand some of the lingo. Different software codes have different strengths and weaknesses. All of them are limited by math. When you make a CAD model, you are essentially engaged in very high level graphical programming. It helps to think like a coder.

2D-basically an electronic drafting board. CRAP!!

3D-contains all data to make a part. 2D drawings can be generated from and are associated to the 3D database.

The model-a math based graphical representation of what you want to build

Parametric-The model is based on mathematical relationships and definitions called parameters, which you can change. The model updates (you hope) when you change these parameters.

Surfacing-Typically complex 3D free form shapes. Very tough to model mathematically.

Solids-A water tight solid database. Allows calculation of volume, wt, moments of inertia.....very useful.

The high end packages combine solids, surfacing, and parametric modeling along with the enterprise level stuff. There are a lot of automated tools for every kind of thing you can imagine. VERY POWERFUL. VERY EXPENSIVE.

The mid range packages seem to be OK at both, not quite as good on enterprise level stuff.

The low end packages tend to be differentiated. Some do parametrics. Some do surfacing. They don't do both. None have the enterprise level solutions...FINE we don't need it.

In here is Rhino; a very powerful surfacing package. I love it. Solids suck. No assemblies. No parametrics. You must understand that parametric modeling is double edged sword. It is great when you need it, but modeling can become a nightmare with it as well. Everything is tied to everything else. When you change one little thing every thing else changes....or not. Best bang for the buck. If you want to build an airplane and you don't have the money to buy anything else...get Rhino.

Alibre. Parametric. Assemblies. A great deal for the money. It has it's problems. Very basic, surfacing sucks, but that is what Rhino is for. Great for mechanical components. I highly recommend.

There are a lot of low end 2D packages......don't bother. Just use a drafting board. Manual drafting tends to bring out the artistic in a person. CAD kills it.

If you want to do analysis.....forget it if you don't have the background. I'm not being a snob here, there are just too may pit falls, even if you know what you are doing. You may be the lone super genius who can do it. There are some of those, but chances are you aren't. The tools peons like us can afford actually require you to know more about what you are doing than the pricey stuff. The expensive software people hire the PhD's who can't comb their hair or bathe regularly to make it easy for the semi-smart mouth-breathers like me to do analysis. If you are working on the low end packages, you better know your stuff. nuff said.

EXECUTIVE SUMMARY:

If you have more money get Alibre also.

Either one of these will let you use CAM which is the real advantage here.

If none of this turns you on:

Bottom line, you can build an airplane with a piece of paper, a pencil, a chalk outline on the floor, and good sense.

Add a slide rule and some imagination and the SR71 is possible.:cheeky:

Monty

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4. Jul 28, 2010

Rienk

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Monty, that is a great synopsis - exactly what I was looking for.
And I will probably follow your advice, especially now that I found and read the other threads mentioned in the last post (I don't know why I didn't find them in my previous search).

I have an admission to make - and since apparently all the other "pros" aren't reading this thread - I'll make a confession.

We have designed and built three planes using 3D software - a six-seat turboprop, a snap together wood and fabric, and a single seat sport plane - and we didn't use any of the software you or others mentioned.

You see, I'm an entrepenuer, and though I've been involved with building airplanes off and on since high school, most of my endeavors have been involved in other industries.
One of those startups is a movie studio - starting with a CG animation film. The software we use to do this? A program called Lightwave.

The software we used to design these aircraft? Golly gee - Lightwave:emb:

That's not to say we didn't use other tools... we use Autocad a lot, and our Aero and Structural engineers use other software as well - but all the design work, all the plugs, molds, parts, etc, were just with LW and AC (such humble beginnings).

Thus, I know from experience that even simple tools can be used to design aircraft - with a little help from friends!

Still, I am interested in moving up in the world - because there are certain things that we can't do easily or well; more importantly, I can't afford to have my partner keep putting off the movie CG work to design airplanes - so we need tools that other people (airplane nerds, not movie nerds) can use.

To be honest, our meager success (to date) has more to do with clever people doing clever things in ways that most people wouldn't think of... it doesn't hurt that we are already experts at 3D (not me, but others), have almost all the CAD/CAM and other tools we need in-house, topped off with a love for designing and aviation!

Frankly, I' would love to work with some engineers like several of the well known ones on this forum, but I can't seem to afford them:depressed
It seems that most of them think that engineering should cost almost as much as the rest of the development project!
In fairness, their rates may be normal, but my development costs aren't. The 'Envoy', or six seat turboprop, has only cost us about $600k to date - and that is design, engineering (from friends and acquaintances), plugs, molds, several proof of concept builds, several mockups, multiple airshow appearances, and a near ready to fly prototype (with turbine, full glass cockpit, leather interior - the whole sheebang). The Solo - our single seat POC, which we plan to retail RTF for around$25k, will cost an order of magnitude less to develop.

Anyway, we would like some new tools, and some additional help - thus the inquiry about Design software being used by others.

Thanks again for your feedback; along with the other thread I read, it has been very informative. We hope to be able to utilize it soon on the other three designs we have on the back burner!

Too many planes - not enough time (or money). Thanks again!

5. Jul 28, 2010

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Well, I've had much less experience with CAD software as I have had in depth experience with only 2: AutoCad (before they went 3d) and Solidworks. But I do have experience with 3d modeling programs like 3D Studio Max and Maya back when I fancied myself a graphic artist.

What I've come to realize is that its much easier to make a pleasing shape with non parametric programs, but if you want to correct something you'll have to pretty much throw it out. With 3d programs, you can make a boxlike approximate and then smooth it out until it looks the part. I think that if you really wanted to, you can design something workable in these programs, but it'll be more trouble than its worth and without a lot of tools that CAD programs have.

I've worked with both CATIA and Solidworks, though more with the latter than the former, and what I've seen is that there isn't much difference between them in terms of surfacing. You do have more control in CATIA, but unless you're trying to develop radar defeating aircraft, what's in Solidworks is more than enough. The thing I like about Solidworks, and has kept me from going to other packages, is that its a centralized and intuitive package. In the same program you can draw the parts, assemble them, analyze FEA in both physical and fluids, and even interface with a program like LabView to program controllers for your device. To do the same with other programs will require you to export/import your models into a plethora of programs like ANSYS, NASTRAN, etc. To use all these features, though, you have to pay around $5-$7k. You can, however, run FEA on single parts in the educational version, which is around $200. After I went from AutoCAD to Solidworks, I can't imagine not designing in parametric. I never thought of it like programming, but that actually makes sense as your part has to follow a logical construction, which also simplifies manufacturing. If you have that figured out, you can literally draw a part as fast as your fingers can move. What I've found to be the most time consuming is doing complex surfaces: where you do one thing, see if it works, fix the error if it doesn't, and repeat. That and making changes at the head of the parametric stack, which often causes errors in the rest of your part that you then have to go down the list to fix. It beats redrawing the part from scratch, though. dsigned and Chlomo like this. 6. Jul 28, 2010 Inverted Vantage Inverted Vantage Formerly Unknown Target Joined: Jun 20, 2008 Messages: 1,116 Likes Received: 32 Rienk; glad to see you use Lightwave. I use modo, which was made when a bunch of high profile Lightwave guys left the team to start their own studio. As for myself, I use, in order: paper/pencil to get the idea, modo (a polygonal modeler used in the effects industry) for roughing out the 3D shape, Rhino for turning that into a properly dimensioned, usable NURBs object, then Solidworks at the company I'm working for now to actually turn it into something manufacturable (by importing the NURBs object as a reference). From one 3D art guy to another, Rhino will probably be the easiest for you to transition to - Solidworks is a bit of a PITA for newcomers (it's relatively easy to use, but you have to have someone teach you to think like the program). Have you ever worked with NURBs surfaces before? That being said, Radi's points about Solidworks are well founded; I love working parametrics - it's annoying at times but when my boss wants me to adjust the angle of something, it's just a quick number change instead of having to go back and rebuild the entire thing. Last edited: Jul 28, 2010 7. Jul 28, 2010 Monty Monty Well-Known Member Joined: Jul 15, 2010 Messages: 1,283 Likes Received: 478 Location: Fayetteville, AR / USA Great posts everybody. Some things I forgot to mention. For doing free form shapes, the one tool I can't live without is conics. That is where Unigraphics used to leave everybody in the dirt. You could do parametric surfaces without having to do a sketch. Everybody including Unigraphics has gone to a sketch based format. At one time the stand alone curve was parametric, ie you could change the end points, and the rho value and the surface and the rest of the model would update. The tools available for blending were fantastic. You could do variable conic blending! This is usually where the mid tier packages tend to suffer compared to the high end stuff. Wing root fairings for instance. SolidWorks uses the parasolid modeling engine just like UG. I really like Parasolid. Catia is a pain. It is very powerful, but its kind of like a HP calculator. Everything is backward and upside down. It would be easier to do a sheet-metal airplane in something like Alibre. Since everything is flat wrapped you don't need super duper surfacing, but having to do all the surfacing as splines in a sketch would be a nightmare. Fully parametric free form modeling can be an absolute PITA. The model blows up every time you change some little detail. It helps if you structure the model right from the beginning, but it is still touchy. I do a lot of plastic parts. I can usually use some combination of tapers, and blends along with sketched curves to get a pleasing shape even in Alibre. For the more challenging parts I do the shell in Rhino and then fill in all the details in parametric form in Alibre. Although you could theoretically do all that in Rhino it's just too painful to have to keep doing things over and over again. Rhino does conics. Unfortunately they are not parametric. There are a lot of great tools for messing with surfaces and the blending tools are improving. You can always construct your blended surfaces from curves if you have to. No reason you can't use Lightwave, I think Burt uses Ashlar Vellum. Anything that makes a true 3D database should work. If you are really good and understand the process all the way to CNC, you never even need to have a dimension in the whole thing. It is sort of like craftsmanship and direct measurement taken to the digital realm in a repeatable way.:ban: Drafting is dead...but the Zombie lives on.:tired: Monty 8. Jul 28, 2010 Monty Monty Well-Known Member Joined: Jul 15, 2010 Messages: 1,283 Likes Received: 478 Location: Fayetteville, AR / USA Hey...I'm an entre-manure too! I've ventured a few products. Currently wading back into the manure at present. We'll see how this one goes. To keep food on the table between times I do free lance product design for small to medium sized companies. Your projects sound like more fun than my typical project. Engineers are expensive, but in my world they are peanuts. The real money is in the tooling and the inventory. As you move up the technology scale engineering gets to be more of the cost. I have an engineering background, but most of what I do falls in the industrial design and product development realm. PE's are expensive, because they have to have liability insurance and license fees etc. Plus its not easy to get an engineering degree and OJT experience is worth a lot. Still, they are like lawyers, when you need one you hire one and just accept the pain$. In my experience I would rather deal with the engineers. I can write contracts, but I have the lawyers look them over. Same with engineers. I can run the numbers, but if peoples lives are at stake, you pay the professional to look it over or test it. Almost all my stuff winds up going through agency testing like UL or CAE. It gets tested six ways from Sunday before it sees the customer.

On a different subject, what did you use for CAM to get from lightwave to G code.

Monty

9. Jul 28, 2010

Inverted Vantage

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Nice to see some more ID people on the forum...

*Is an ID student

10. Jul 28, 2010

Rienk

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We have Modo as well, and switch between programs a fair bit for certain functions. However, with the new engineering plug-ins available for Lightwave, we can get pretty good results. The biggest issue is making sure you get enough detail so that the poly's don't become an issue in your plugs.

On a side note, take a look at the plug in we developed, called 'Maestro' (Welcome to Stillwater Pictures) . It is an amazing tool for rigging and animation - allows us to animate almost ten times faster than standard tools (that is why we even thought we could produce a CG movie for less than $1M... the bummer is that the new build of Lightwave won't continue to support it). Back to software; we'll probably pick up Rhino, and maybe Alibre... once we actually start selling planes and can afford to hire some in-house talent, we probably will also get SW. Most of my friends use Catia, but that is not likely to happen for us unless we're wildly successful - I'd rather save my money for a large format 5-axis router. Which brings up another tangent - I have tons of parts and stuff for building some very large CNC mills... if anyone is interested in actually building something out of them, maybe we can work out a deal onder: We're having to consolidate some of our facilities, so we're moving a lot of our stuff into the hangars, so we won't be able to get back onto the Solo project until probably September :ermm: 11. Jul 28, 2010 Rienk Rienk Well-Known Member Joined: Oct 11, 2008 Messages: 1,364 Likes Received: 190 Location: Santa Maria, CA (SMX) Okay, here is the redneck way to build an airplane (even though I was involved in building a plane in highschool during the 70's, I often drove to school on a tractor!). Design parts in Lightwave (with help from Modo) Export as DXF. Scale up in AutoCad. Import to either BobCad or MillWizzard, and adjust for cut file. Export to Shopbot file. No G-code involved (though it could be). Load up in Shopbot, and cut plugs! That's when the real work begins :nervous: For a photo tour of the first time we went through this process, take a look at the "plug/mold" photo gallery of the 'Envoy' (http://sreyaaviation.com/envoy/main.html). 12. Jul 30, 2010 Rienk Rienk Well-Known Member Joined: Oct 11, 2008 Messages: 1,364 Likes Received: 190 Location: Santa Maria, CA (SMX) Hey guys, Is it possible for us to take the 3D polygonal meshes (parts) we create in Lightwave (exported as DXFs), and import them into Rhino or Solidworks, and then convert them to solids or surfaces there? I'd love to do our initial design work using the software we already know well (we can create parts almost as fast as people can sketch them), and then do some of the heavy hitting in the other software. 13. Jul 30, 2010 Jay Kempf Jay Kempf Well-Known Member Joined: Apr 13, 2009 Messages: 3,531 Likes Received: 865 Location: Warren, VT USA Packages like Solidworks (and the little brother Alibre) are really good. Many people have opinions about Solidworks that come from not having gotten through the learning curve on lofting. I can do anything I can think of in Solidworks. Doing it correctly means that I can take the actual geometry and do whatever I want with it. I can present photo realistic views, I can take parts or assemblies and do strength analysis on them. I can look at weight and balance... etc. Fluid dynamics is another animal altogether and a friend and I are looking at OpenFoam for that but that is a world where small misunderstandings can make the results useless. I am sure Catia is another level above but it is tailored for building large airframes and the relevant systems. My rig is dual quad core 19" rack Dell workstation with a massive Nvidia graphics card and a couple 24" diag DVI monitors and a huge amount of storage in the terabytes. Works great. Hardware is cheap these days. Surfacing packages give you great looking pictures but how do you know the math that made the surfaces? If you are looking to visualize an idea that works well. If you are looking to analyze performance or actually build the thing you need to know what you built. You can do that with a calculator and a notebook, some full scale templates and a nice square footage of shop. Or you can play in computers for a while before cutting expensive materials. I choose to play in the computer while conceiving. I used to be an AutoCAD guy. Don't really touch it anymore. 14. Jul 30, 2010 davedpilot davedpilot Guest I bought the premium SolidWorks 2010 and I agree, SolidWorks is a great program for surfacing and a host of other CAD stuff. DESAULT bought SW from some guys in Boston I think and built CATIA V5 on the SW platform for PC's; a big jump from the command line UNIX version of CATIA V4. I've used both and continue to use V5 in my day job. SW is much easier with the same results. SW may not be as powerful as V5 but all you need is construction geometry to build the surfaces. Basically, the more guide curves you give it the more complex the surface you can create. You build on base geometry and when you update it, all the children automaticaly update and with few spline tweaks your good to go. My 2 cents, you can pay me later. 15. Jul 30, 2010 Monty Monty Well-Known Member Joined: Jul 15, 2010 Messages: 1,283 Likes Received: 478 Location: Fayetteville, AR / USA So would you care to elaborate on what is wrong with the math behind surfaces created in a surfacing package? Monty 16. Jul 30, 2010 Monty Monty Well-Known Member Joined: Jul 15, 2010 Messages: 1,283 Likes Received: 478 Location: Fayetteville, AR / USA Yes the Parasolid modeling engine rocks. It really works great. UG, Solid Edge, and Solid Works all use this kernel. The only difference is the user interface and the tools that come with them. It sounds like they are moving more towards the way Unigraphics used to work. It was kind of like Rhino except the curves were parametric and the surfaces remained attached to the curves and vice versa. So you could grab an edge curve and do things with it. You were not confined to a sketch plane. You didn't need fifty bazillion construction axis, planes and such just to make a simple 3d frikin curve. You just made the curve...imagine that! Plus the way it handled solids was fantastic. You could start with a curve you grabbed off a complex solid, use it as a guide curve. Or my favorite was you could specify multi dimension offsets so the curve became a sheet of some thickness. All solids, all parametric, all tied together. You could also make multiple tools and do intersections etc. It was fantastically free flowing. You were not tied down in some tar baby approach dreamed up by the software geek who thinks HE knows best how it should be done. The other fantastic thing was all the tools for working with the solid surface after it was created. You had to have the advanced surfacing module to do all this which most people don't have. I'm sure Catia is the same way. The base version of UG isn't any better than Solid Works. It's the ala cart stuff most people never get to play with that set them apart. For instance UG has a 5+ axis CAM package that allows for arbitrary 5 simultaneous axis cutter compensation in the post....can solid works do that? How about complex surface topology tools. Or the ability to mathematically generate surfaces (radomes, LOW RCS etc). How about intersecting complex surface blending? Conic Blends? Soft Blends, Law controlled blends...there was one whole menu of tools just for blending. All parametric. I REALLY miss that. Solid Works doesn't do these things guys. I like the package and I hate the way the big guys do business, but they really are in a different league. I've seen really impressive stuff done with Catia, so I know it can do it, but the user interface and I never did really come to terms. Solid Works has a great user interface. So does Alibre. It's just limited. My personal weapon of choice would be an early version of UG NX. Before the "we have to all be like Pro E" thinking infested the industry, and before the lets just keep changing everything around so we can sell training strategy really got going. Last time I checked a full blown package of UG with all the trimmings was north of$50K and yearly maintenance would eat you alive. At that point I had somebody supplying me the license to do the work and I had the advanced surfacing package to play with. I didn't have cam or analysis, or sheet metal, or, or, or.

When I stopped working on that particular contract I had to buy my own software, and now I consider Solid Works too expensive.

Monty

17. Jul 30, 2010

Monty

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Rhino will import a lightwave file directly. It will also import raw triangles and meshes. You can generate a nurbs surface directly from the mesh. There are large number of tools to tweak the surface and also check it for smoothness, tangentcy, curvature, etc. you can offset it, cut sections to create bulkheads, unroll it if developable etc.

Rhino will export almost anything. The file translation ability of Rhino alone is worth the purchase price.

So have you had problems making parts from your poorly defined surfaces?:roll:

Monty

18. Jul 30, 2010

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Kind of off-topic and not helpful for anyone looking for software right now, but FreeCad is worth keeping an eye on. It's free open-sourced 3D CAD, based on the pretty much FOSS OpenCascade.

Does a whole lot of not much so far but in a couple of years should be a reasonable option for people with tight budgets.

19. Jul 30, 2010

Inverted Vantage

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You can import polygonal meshes into Rhino but not Solidworks, and once they're in Rhino you're going to have to rebuild them completely with NURB surfaces. It's not that hard though, depending on how complex the object is.

20. Jul 30, 2010

Dana

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I've said this before in the other software thread, but unless you're quite experienced with the program, and know in advance what kind of changes you're likely to make, parametrics will likely longer, even after several rounds of changes, than a non parametric system. With a parametric system like SWX, you can often find yourself boxed into a corner, unable to make the changes you need, and end up having to rebuild the entire model. With a non parametric system you can't always change an entire shape by changing one number in a sketch, but you can simply lop off the offending section and redo just that without affecting anything else. Parametrics has its place and can bve useful, but it's more hype than substance.

Unless it's improved a lot since I worked with SWX a few years ago (doing automotive body design), is surfacing tools are nowhee near as good as Rhino. Not a criticism, it just wasn't aimed at that market. At the time, I was using mainly Cadkey/Fastsurf and Unigraphics, with some Rhino thrown in. Today Cadkey is now called KeyCreator... think of the sufacing tools of Rhino but with a good non parametric solid modeler, assemblies, and detail drafting tools (which Rhino always lacked).

-Dana

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