Wireframe model

[johnny99]

I'm looking for wireframe model's of saloon cars, mainly a classic shape Impreza, Lancer Evo 5, and a Ford KA. Does anyone know where I could get these.

John

[RH1300S]

Google 3d Models - you will find loads of varying quality. Some free and some you pay for.

Hope that didn't sound patronising - not meant to be

Otherwise you can get 3D models from computer games - try rFactor for one, there are loads of mods available, so loads of models. Bear in mind you are using other peoples work, so seek the author's permission (unless the models come royaly free).

Most games will have a separate utility that lets you import a model from the game format into your favourite 3d editing program. I haven't done any mods for a long while (and none in rFactor) - but I am pretty sure you won't need to buy the game. Just find the tools as a plugin for your modelling software and import the downloaded car file with them.

Again - have a look at z-modeler for 3d modeling, most games can be imported into this, then you should be able to export the mesh into a more well know 3d format.

www.rfactorcentral.com

www.rfactor.net

http://www.rfactor.net/index.php?page=devcorner (I think these are the tools)

[johnny99]

Maybe I should have said, I need it for CFD, can I do this

John

[RH1300S]

I don't know - anybody here able to help?

A model from a game (and probably other sources) will be a polygon mesh and not very high poly count (some far better than others). Also, underbody details may not be brilliantly resolved (would that affect CFD??)

Games models often play with normals to make then appear smooth in game with fairly low poly count.

[kilcoo316]

When the feck did you Westmeath commanches get the internet?!?!


Are you doing university work on ground vehicle models?

[johnny99]

When the feck did you Westmeath commanches get the internet?!?!


Are you doing university work on ground vehicle models?

Fairly rich coming from your part of the world. We do a bit of racing, and I would like to play with aero, so I thought it would be good to see what I could do and a computer, and then see what improvement come on track. I have done flat floors with diffusers (one is adjustable) and they do make a difference on track, and I would like to play with more.

By the way, we also have electricity since last Tuesday,

John

[kilcoo316]

Are you just looking to get your tools up and calibrated?


I would strongly suggest you try to hoak out information on the Ahmed body testcase. Its a very well known validation study for ground vehicles.

http://www.cfd-online.com/Wiki/Ahmed_body

It has been used as a basis for numerous turbulence workshops:

http://tmdb.ws.tn.tudelft.nl/workshop10 ... se9.4.html


There is also a variant called the Toyota body, I might have the data on that kicking about - I'll have a look.



Hows your French? I've worked on a wedge testcase before - google "IMFT" and "diedre" and you'll get a couple of presentation pdfs outlining it... there are even a couple of my old results thrown in there!


Again - I strongly suggest walking before running. The Ahmed body is a well used test case for good reasons - there are flow differences from the 25deg to 35deg backward slope geometries.

That turbulence workshop website contains the geometric data. Its a relatively easy mesh to make and it'll allow you to calibrate your models. If this is for uni, that'll impress your lecturer, as your considering the golden rule of CFD:

No validation = No use




I'm guessing when you say "we do a bit of racing", your talking about a formula student team?

[johnny99]

Formula Student, I wish, I'm a bit too old for that. we compete in the Irish Time Attack series, and are the 2008 Champions, defending our title in 2009.

What I want to do is import a wireframe model of a saloon car, add a flat floor, diffuser, splitter, and rear wing. Then on the computer, lower the front or rear, or both, play with different angles on the rear wing etc, and be able to measure differing level's of downforce and drag. I have access to Solidworks, and a guy who knows it pretty well. Maybe I'm am running before I can walk ?

John

[kilcoo316]

Hmmmm...


I recommend you run those validation models first to get an idea of just how wrong CFD can be.


Taking numbers straight from a simulation without validation of some sort is difficult in the extreme. Although, if you develop an aero-map with CFD only, the comparative setup performances should be closer.


What chassis are you using?

[johnny99]

We run a Impreza, Lancer Evo, and a Seat Ibiza at the moment. Maybe looking at some kind of single seater championship for 2010

John

[kilcoo316]

OK, your gonna have to find out what file formats your mesher/pre-processor will work with...

Probably under File > Import.

Then google "3D CAD Impreza" brings up a load of links to potential geometric sources.


I still recommend you give those test cases a go, to see if your software can actually do the job or not.


I'm also wondering about what assumptions can be used... namely the front grille boundary conditions... anyone here correlated numerical simulations to wind tunnel tests of engine bays before?

[Ciro Pabón]

I moved this topic to Automotive news and technology forum because it is not related to Formula One.