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928 CAD model development, CAD jockeys unite! ;)

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Old 04-01-2009, 12:34 AM
  #16  
karl ruiter
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I would be willing to help out. I am running SW 2006 (since that is what my injection molding house uses), and have some small degree of skill with it. At the moment I only have my convertable, so I could probably only make measurements from mirrors forward. I want to rework the lines of the convertable from the mirrors back, so a 3D model would be super useful to me.
Old 04-01-2009, 12:38 AM
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Originally Posted by testarossa_td
That's the problem. I would have loved to play more with the 3d.....spent the money and then got married...there went the time. Then I got solidworks LOVED IT went to some classes in Dallas...no time.

Maybe one day. Maybe one day...
I'm not following... you love SW, but are too busy with SW classes? Drop the class, I'll give you a SW lesson.

Ohhhh, or is it because you are married.


I hope you know I'm just kidding... with a little chiding because I need help.
Old 04-01-2009, 12:43 AM
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Jadz928
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Originally Posted by karl ruiter
I would be willing to help out. I am running SW 2006 (since that is what my injection molding house uses), and have some small degree of skill with it. At the moment I only have my convertable, so I could probably only make measurements from mirrors forward. I want to rework the lines of the convertable from the mirrors back, so a 3D model would be super useful to me.
Cool Karl. I've seen you 'round these part for some time and had no idea you knew CAD. I know, we don't like to share that useless piece of knowledge here.

Is you 'Vert based on OB or LB?

If your interested, what would you like to do?
Old 04-01-2009, 04:23 AM
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Nicole
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Didn't RedUFO create a 3D model of the 928 some time ago?
Old 04-01-2009, 04:33 AM
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I'd offer to help but I don't think my 3D modeling skills are anywhere near whats needed... cool project though!
Old 04-01-2009, 12:09 PM
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Hi....

What would be the end purpose of the model....? Just for making pretty pictures or perhaps in the future to be able to use for manufacturing/ prototypes / studies...??

If there is no desire to manufacture parts from the models, then your process should be quite simple, just the basic dimensions and lots of guess work until it looks right.... kind of like doing photoshop but in 3D.
Not sure that it will be an easy process in Solidworks.... something more like studio max would be a lot quicker....
Getting a scan of the car would make it alot easier/faster and accurate.... you could even use the polygon scan model and render directly from that.... no modeling needed.

Having an accurate model is however a different story... and Nurbs based Math Data surfacing program is really what you need.... Like Rhino or Auto studio (Alias) On a paying job skilled operators will charge in excess of $50 / hour for this kind of service.

I modelled up some 'packaging' models of my intake area to help develop an intake like DR's.... as I couldn't wait for him to get his production in order....
Pretty rough, from measurements, just to help me visualise that everything would fit.....



I've been using Unigraphics for the past 12 years and Alias of and on for about 2.... I can probably help out with some smaller pieces if needed.... or rather I know I can modelling wise... but time is something I don't have a lot of...
Old 04-01-2009, 01:05 PM
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karl ruiter
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Not sure, Jim. How would you want to break the work up? Do you want to do individual parts (hood, doors, fenders, chassis, etc) or do you want to do the overall car? My 'vert' is based on a OB, with an ugly AIR fiberglass S4 replica rear bumber. My goal would be to have a model I can modify, look at, inspect, post, etc. before considering setting into the car with an angle grinder. I think it might be feasiable for me to model the front fenders and hood, although in this sort of case I am not sure how you establish a reference to measure from. Also, without a model of the bare chassis I am not sure what you would hang those parts on. What do you think about collecting a whole bunch of digital pictures of individual parts (hoods, fenders, bare chassis, bumpers, etc) , from 2 or 3 angles each and then measuring and modeling off those. One cool thing about part photos idea is that this would be a relatively easy way for non cad users to contribute. I think it would be very cool to eventually have a complete model of the whole car with all the individual motor and tranny parts and everything. Non SW users could use the free eDrawingViewer and would be able to virtually disassemble, cross section, etc their cars. Too much work, but it would be cool.
Old 04-01-2009, 02:26 PM
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Thinking a bit more about this.... I think the first point to consider would be to find some cheap 'close range Photogrammetry' software....

Using this you place small 'stickers' over the entire vehicle... these become reference points.... you then take lots of photographs using a digital camera from various angles.

Photographs are then loaded using the software and I believe you basically align all the reference points.... the software can then create a 3d image, most decent software can output this 'image' as a .stl file.... or polygon...

All you then have to do is render this directly of use it as a base to section through and create surfaces.....

In my line of work we usually use highend laser or white line scanners... read.. Megabucks!
But I was recently at a technology expo where I was shown some fairly cheap Photogrammetry alternatives... obviously not as accurate, but more than enough for this project.... Software that I have seen runs for about 1K.... but i'm sure there are cheaper alternatives out there.....
EDIT: Just found the software that I had reviewed at the Expo... interesting reading... http://www.rhinophoto3d.com/

Last edited by FUSE69; 04-01-2009 at 02:54 PM.
Old 04-01-2009, 04:22 PM
  #24  
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You are overthinking this.

There is a much easier way to do this. We get a good plastic model from ebay for about $20. Or we borrow a built one from one of us "fanatical" rennlisters. I have a MicroScribe MX digitizing arm which says SolidWorks can make pretty quick work of this. The model companies spend a lot of time making accurate scale models. It will be simple enough to scale the part up after it's done... What kind of wheels do we want to go with? I, of course want to go for the design 90 or cup2...
Old 04-01-2009, 07:02 PM
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Originally Posted by Nicole
Didn't RedUFO create a 3D model of the 928 some time ago?
He did and I hope he chimes in here. It was an excellent effort.

Originally Posted by The_Remora
I'd offer to help but I don't think my 3D modeling skills are anywhere near whats needed... cool project though!
Like I said, a napkin, pen, and tape measure...

Originally Posted by karl ruiter
Not sure, Jim. How would you want to break the work up? ....
The idea was I would lay out the master surfaces. Meaning, take away all the detail and model primary shapes and contours. Should be able to this in less than 20 hours.
What I ask from others is to model detail parts. Like I said before, things like wheels, tires, mirrors, lights, etc. They are all little projects on their own.

Originally Posted by karl ruiter
...What do you think about collecting a whole bunch of digital pictures of individual parts (hoods, fenders, bare chassis, bumpers, etc) , from 2 or 3 angles each and then measuring and modeling off those....
Pictures will help. You can reference them to stay on track. There will still be benefit from grabbing a few reference dimensions off the actual part.

I have a few ideas on ways to do all this. They will require some pics I have to works up. Give me a little time, and it will start making more sense.
Old 04-01-2009, 07:12 PM
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Originally Posted by FUSE69
Hi....

What would be the end purpose of the model....? Just for making pretty pictures or perhaps in the future to be able to use for manufacturing/ prototypes / studies...??
Pretty pics, color studies if someone want to see a different paint color on their car, body mods... nothing for manufacture.
Something like this.....

And you're right that does make it easier.
And yes, there may be better softwares for this application.
SW is free to me and I have alot of experience in it. For me, it's just about time and having no budget.
I'm working with what I have and using this as an opportunity to challenge myself.

You're work on the intake filter design inspired me to design one too.
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Old 04-01-2009, 07:17 PM
  #27  
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Originally Posted by 86'928S MeteorGrey
You are overthinking this.

There is a much easier way to do this. We get a good plastic model from ebay for about $20. Or we borrow a built one from one of us "fanatical" rennlisters. I have a MicroScribe MX digitizing arm which says SolidWorks can make pretty quick work of this. The model companies spend a lot of time making accurate scale models. It will be simple enough to scale the part up after it's done... What kind of wheels do we want to go with? I, of course want to go for the design 90 or cup2...

Mike,
I have the AutoART 1:18 model which could be scanned and scaled. My guess is it will only serve as a reference point for where everything is generally located.

I though CupII's would be a good wheel to model. Simple and classic. I don't have one to model though... Have at it.
Old 04-01-2009, 07:22 PM
  #28  
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I've done modeling a lot...

ussspeed.deviantart.com

And I also work in that field. (Video game)
So, I could give some help.
Old 04-01-2009, 09:42 PM
  #29  
Jadz928
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Default Getting started...

Since I'll be using a 2D sketch based software (Solidworks), I wanted to give you an idea on how things get started.
Essentially, I have to lay out all the profiles and contours of the car. Shown below is the center profile. It's shown because it's the easiest.

The modeling concept is similar to laying out the inner structure of an airplaine fuselage.
Profiles and contours in X,Y,Z, then connect the dots with simple surfaces.
Then break down the simple surfaces into smaller sections, like the hood would be one surface, the windshield is one surface, fenders... etc.
In some cases, even those surfaces would need to be broke down further.

So how do you measure all this stuff.... seems impossible.
Basically, you measure what you can. What makes sense?
Length and width of the hood. The hood tapers so the width varies. So you measure the width at both ends. To finish, you tweak it until it looks right.

As you can see there are alot of measurements, but if you break it down into smaller pieces, it's not that bad. Get a few more people involved and it will go well.

Someone asked how do we coordinate?
Basically, 4 ways:
-A master model which contains all simple surfaces, primary dims (wheel base), and contours.
I will develop and manage this.

-The master model also has an origin, which we will call "vehicle coordinate system" or VCS.
This will be the same on most every model generated. At least the critical ones that reference of one of the simple surfaces.
Right now the VCS as halfway btw the wheel centers. It's the only primary dim thats the same thru all MY's (2500mm).

-Communicate models back and forth using export data such as IGES or STEP (this is where the VCS works).

-Role assignment. Who's doing what? I will keep a master list on this.

Clear as mud?
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Old 04-02-2009, 07:57 PM
  #30  
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Here is a link to an existing OB 928 model. I uploaded some models and am waiting for some credits so I can download it. It's a little blocky, and the rear wing is all wrong...
We might be able to use some of it.

http://www.3dcadbrowser.com/preview....odelCode=15312
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