Custom Body - Methods and Means - Software, Programs and Techniques

[kach22i]

I just want to know how Audi gets away with those big fish mouth openings first.

[PhyrraM]

From the ones I have seen, only about 30% of that huge Audi fishmouth is actually open for airflow. The bumper area is just a black plastic swath with a traditional bumper hiding behind it.

As far as the 818 goes....Reduced crashworthiness is just part of the deal with these types of cars. IMO, of course. In fact one of the reasons to go with a kit is be able to do things that OEMs no longer can. Low hoodlines, for one.

[kach22i]

From the ones I have seen, only about 30% of that huge Audi fishmouth is actually open for airflow. The bumper area is just a black plastic swath with a traditional bumper hiding behind it.

I've looked carefully at some Chrysler's before, and the 30% applies there. I'm not so sure about Audi, in either case the grille looks very sacrificial to me.

Sample-1:
http://www.flickr.com/photos/16885292@N02/4121405972/

Sample-2:
http://www.carwear.com.au/~carwear/n...7-grilles.html

Sample-3:
http://www.tuningshop.co.uk/acatalog...cessories.html
audi_a4_front_grill_rs4_black.jpg

Sample-4:
http://www.audituningmag.com/s-line-...k-mesh-grille/
audi-s-line-grille.jpg

The horizontal bar for the bumper is at best 30%, leaving 70% open. Again, it's not the percent of openness I'm curious about. It's the "out there and looking to take it in the chops" look which raises my eyebrow. It's just too flush to think of it as part of a true protective bumper system, at least from a cursory visual impression.

[PhyrraM]

I think that all cars have migrated to the plastic skin being sacrificialwith the real protection in the beam underneath. It just took 20 years for the traditional "bumper protrusion" to eventually dissappear. It did on sports cars first and gradually moved to sedans and others. Trucks will be next....

[shinn497]

I have to wonder. If you could somehow make the molds, would it be possible to make a carbon fibre body?

[kach22i]

I have to wonder. If you could somehow make the molds, would it be possible to make a carbon fibre body?

I think you can substitute carbon fiber cloth, Aramid, Kevlar or other cloth for fiberglass cloth/mat. The added strength of these exotics most often comes from the added stiffness of using epoxy resin over that of polyester, and also possible autoclave baking (curing).

The question is, for which part do you want added stiffness, and for which parts do you want added flexibility?

If you are just thinking these alternate cloths are lighter, they may be, but perhaps only because they require less resin. This advantage may not be so great if filling in all the cloth pores for a perfect skin finish. I'm no expert and have never done vacuum infusion myself, but have seen it done.

I'll wait for someone with personal experience to talk about the finish quality issues and cost issues.

[BipDBo]

I have to wonder. If you could somehow make the molds, would it be possible to make a carbon fibre body?

You can lay carbon in the same way that you lay fiberglass, but not all techniques are equal. The quality of the final product is greatly dependant on the quality of work going into it, whereas fiberglass is a bit more forgiving. Carbon is not significantly lighter than fiberglass, but it is stronger, so you can use less of it. One caviat is that if you are dealing with complex shapes, it's very difficult to make the weave look right. If it's painted or covered in gel coat, you don't need to worry about this. Most carbon products wouldn't be covered in gel coat because that's alot of weight. The best carbon techniques provide a consistent coating of resin on all of the carbon fibers, but leaves no voids and uses no more resin than is neccessary.

After laying out carbon, it's best to put the product in an oven for a heat cure. I don't know why this is done with carbon instead of glass, but I suspect that it is done when using carbon that is pre-impregnated with resin and delivered on a on a refrigerated truck. Pre-impregnated carbon assures that you do not have any dry fibers, but you use the absolute least amount of resin that you can get away with. This results in the strongest, lightest carbon products. Heat curing also might be used with resins that have a long cure time. Not really sure.

Does anyone know if Factory5 lays clothor matt (or a mix of the 2), or do they shoot matt from a one of theose fiberglass guns?

On another thread, I brought up backing the fiberglass skin with a thick foam core. This would increase crash protection while allowing for the use of less glass. This could be done on the front and rear bumper panels and the doors. I really should have brought it up here.

[kach22i]

On another thread, I brought up backing the fiberglass skin with a thick foam core. This would increase crash protection while allowing for the use of less glass. This could be done on the front and rear bumper panels and the doors. I really should have brought it up here.

Spray glass will be way too heavy, hand laid is the way to go but more expensive.

Your foam idea is similar to one I've hand in mind for quite a while, and I know at least one other person has spoke up. It's a good idea, so good that NASCAR has been using it for years.

http://www.stockcarscience.com/scien...ety_IMPAXX.php
impaxxcagepress.gif

[Grantourer]

Not sure what foam Subaru uses in the Legacy, but it definitely helps protect certain parts, not sure about adding crashworthiness or occupant protection.

There were some discussions about it in the LegacyGT forums when some tuners made their FMIC kits without being able to keep the bumper foam.

NHTSA's take on the foam:
http://www.nhtsa.gov/cars/problems/s...per/index.html

P.S. I enjoy this thread, it's very interesting. Makes me wish I pursued Materials Engineering.

[BipDBo]

Spray glass will be way too heavy, hand laid is the way to go but more expensive.

Your foam idea is similar to one I've hand in mind for quite a while, and I know at least one other person has spoke up. It's a good idea, so good that NASCAR has been using it for years.

http://www.stockcarscience.com/scien...ety_IMPAXX.php
impaxxcagepress.gif

There's some good info on this link. It looks like Dow did a lot of research to find out that the polystyrene foam used in the mass market automotive industry is also the best material for NASCAR, so they slapped the name "IMPAXX" on it. I really think that Factory 5 would do well to incorporate foam into some of their body panels and/or encapsulating some of the framing members with it.
Another observation: Foam will absorb kinetic energy and therefore provide protection whether it is outside of the car's structure like a bumper, or between the structure and the occupant. In the case of the NASCAR doors the foam is actually outside of the structure. As well as absorbing energy, the foam help to prevent objects from getting through the body to the driver. This seems counter-intuitive to me. I would think that it would be best to have foam between the structure and the occupant as well, possibly encapsulate the structure. It is noteworthy, though, that the intire cage structure is as large as possible. Notice how the tube steel that forms the doors curves outward.
car-of-tomorrow-01.jpg
hotseat_18_cd_gallery.jpg
Perhaps as well as in the doors, another good location for foam would be under the dash, above and in front of the occupant's legs. Another good location for foam would be between the fire wall and the seats, especially if the seats are as I have suggested for the purpose of reduced weight, one piece molded fiberglass like the Aerial Atom:

ariel_atom seats.jpg

This discussion on foam really started on a different thread, which I copied here:

Originally Posted by Nelff in 1/4 scale model feedback:
"One of the things that I was planning on doing was fill any open area between the body shell and cockpit with expanding foam. I figure that if I get caught in a crash that the foam may help absorb some of the energy. Other than that I was hoping that it would quiet the cockpit. ..."

Originally Posted by BipDBo in 1/4 scale model feedback:
"I have had the same thought. Polystyrene (styrofoam) is used often in bumpers. It has very low density and has a high modulus of toughness, meaning that it can absorb a lot of energy before it fails. It's also very cheap. If Factory 5 manufactured certain panels of the car with polystyrene under the fiberglass skin, they could potentially use less fiberglass for the skin and use less supporting structure. This would make the car safer, but it may actually make it a little bit lighter. It could also make the body panels a more consistent shape if they use the right method. In manufacturing windsurfing boards, they first machine a foam core from a solid, extruded blank. Then they layout the skins of the top and bottom of the board in carbon fiber and fiberglass into two female molds. While the resin is still wet in the molds, they sandwich the foam core between the two molds with a vacuum. The foam core holds the carbon fiber into the right shape while it finishes curing. Without a foam core, fiberglass tend to warp slightly after it is taken form the mold because it continues to cure for a week or more. In the application of car body panels, you would not have a 3 layer sandwich, but rather just one single layer of glass sealed to the foam. The obvious disadvantage to this process is that it has more steps and would be more labor intensive and therefore more costly. This process wouldn't be used for the entire body, though just the front and rear bumper panels, and possibly the doors, since they have no windows that roll into them. Beyond my hobby of backyard windsurf board building, this is not my area of expertise, but allow me to speculate on possible modifications to make this process cheaper. The machined foam core may be replace by a molded core if they can find a way to get a consistent enough foam molding process. An alternative method would be to lay out the fiberglass panel in a female mold as they always do, and before removing the panel from the mold, inject the panel with foam. If the foam can cure faster than the glass, than the panel can be removed from the mold sooner with less worry of deformation. "

[olpro]

There is a lot of discussion here on the translation between ¼ scale and full scale. Frankly this is a problem that has occupied designers for many decades and a lot of effort has been made to deal with this ‘scale’ factor.
It is actually a part of the larger debate on design methodology - which include sketching, accurate scale LO drawings (templates, as they are called here), presentation colors and methods, model photography and presentation, etc. The overall goal is to NOT be surprised when the real product emerges onto the scene. There is a difference even between a full scale painted model and a real production vehicle. Therefore, some studios do full scale models with see-through uppers, to help bridge that gap. Fiberglass full scales prototypes almost always have see-through, if not full interiors.

The finish on a model is obviously important to bring across the feeling the real product will have. This includes the color and all details including lettering, wheels, etc.

One advantage experienced studio personnel have is that they are used to looking at both scale models and full scale clay models in progress every day. The realism of details on a ¼ scale becomes less important because one is used to looking at mockups on the full scale too. The in-progress full scale will not have a see-through upper, just like the smaller model it is based on. Its lamps and other details are probably cardboard and paper, just like the smaller model.

The clay models, whether scale or full size, are modified and then dressed up for review on an almost weekly basis. Dinoc, a plastic film, is painted and squeeged onto the surfaces to simulate a painted finish. Baby oil is sometimes wiped on the Dinoc to make it shiner and read the reflections better. Black or dark gray is used for the “glass”, chrome is done with aluminum foil and black tape is used for cut-lines. Sometimes photos of details like lamps and wheels are used if the real thing isn’t available yet. After the review, usually done outside in a road-like real world atmosphere (if you are designing toasters, you might want to review and evaluate them in a KITCHEN), the Dinoc is peeled off and the clay modelers go back to work making changes. In a week or two, the model is dressed up and taken out again. This review, revise, review process will go through many many cycles before the design is “released” to the body engineers. All this is done with relative constant input from these engineers as many of the clay changes are the result of engineering requirements.

Over the years people have tried scale backgrounds for the small models, to try to set them in a realistic environment. This is generally unnecessary, if not actually distracting. The best backgrounds are simple and non specific, avoiding scale clues of any kind.
Viewing height (and lens height for photos) is very important, again to avoid misleading and contradictory clues. This simply means matching the viewing experience of a “scale” person with the camera’s view. Longer focal length lens are generally better too. If shooting a scale model with real cars in the background, it is important to RAISE UP the scale model on a table so the scale viewing height exactly matches that of the real cars in the background. Doing this, with some attention to relative sizes, can place the scales into the scene convincingly. In fact, every studio has a set of tall display tables which will place the models at a correct viewing height – so no one has to bend down to get the right perspective.
Photoshopping the car into a photo with a real background can be done but the lighting and perspective must be well matched. This approach makes for dramatic presentations but is usually distracting and quite unnecessary for comparative evaluations.

One easy thing to do to “see” the scale model as being full size is to look at it through a camera viewfinder. This kind of creates the reality of full scale and makes it more believable. You are then dealing with monocular vision, and judging the design on the basis of a 2D image, but that is a very common mode in today’s world and most everyone is able to make the leap.

At all the major auto studios, the ability to create small scale models with amazing quality is commonplace. It is no big challenge to take photos of these models in such a way as to fool the average viewer into thinking they are of full scale autos, as long as the photography follows simple, obvious principles. Viewing scale models in real time is still a little harder to do, to make that perceptual leap to full scale. Once, as an attempt to make the viewing more real, I asked the GM Design Staff shop, which has amazing capabilities, to make me up a plexiglass prism which was designed to allow the designer to look at a ¼ scale clay as if he were ¼ size too!
If you are familiar with the glass prisms in a set of binoculars, you know how they take the light paths from the normal interocular distance (2.60”) to the wider distance between the binocular lenses - so the binoculars would not only magnify the image but would still preserve a scale 3D viewing effect. My device did just the opposite by reducing the interocular distance to ¼ of full size. It did not change the magnification. The idea was to give the viewer the impression of being a ¼ scale person - with a ¼ scale head looking at the model. The device kind of worked but had serious limitations with its field of view, etc.


At the limit of the art, some companies have occasionally decided that “dynamic” viewing is necessary – based on the notion that a car in MOTION in a real world situation is the best evaluation tool. Of course this has become much more doable in the digital world of CG animations, some of which are done in 3D. You just have to wear the funny glasses and sit in the right spot in the viewing room to get the best results. This really works well for interiors where one may be surprised when reaching out for the controls and finding they are not actually there. At one point in my career I was the guy sent around to evaluate some of these systems so I have experienced most of them, and that was years ago. This stuff is certainly not new and the capability of making computer animations has reached the desktop of many people, including a number of those who entered the 818 competition and supplemented their proposals with dynamic videos.

The major studios have all gone to big projection systems where the photos or CAD model looks full size. These “powerwalls” are multimillion dollar installations but get funding because they are so impressive to the big wigs invited in at presentation time. Most designers really don’t need this kind of technology to see the designs properly. Of course the Hollywood perception is that there are holographic viewing rooms where one can create the 3D image spinning nicely in the middle of the darkened room. At least that is true in the movies.

In my younger days we worked to the same kind reality by doing full scale tape drawings and airbrush renderings. With these, the designer worked directly over a detailed engineering drawing to hold the necessary layout conditions, making only some perspective corrections because we really don’t see cars as flattened out totally orthographic shapes. The resultant artwork gives a good feeling for the size of the vehicle, and whether the forms and details actually ‘work’ at that scale. Since the Powerwalls and CG technology has come in, I see more cars on the road that were apparently rushed through the full scale development stage and seem oddly out of scale or crudely detailed. There really is no substitute for a five month long development stage of a real full scale clay model, where the designers, engineers and modelers are living eight hours a day right next to the models, and working together as a multidisciplinary team.

[Vman7]

Olpro, I always love reading your long posts on the design process , I always get an education. I am wondering if Dave Smith and FFR has or will ever use your expertise and experience in the design of their products.

[kach22i]

There really is no substitute for a five month long development stage of a real full scale clay model, where the designers, engineers and modelers are living eight hours a day right next to the models, and working together as a multidisciplinary team.

Another nice background post on the industry.

Did the auto design guys ever end up sleeping under their desks like architects? I only did that in my own office, which is why I ended up buying a couch.

[olpro]

Thanks, Vman and kach. I enjoy (and learn from) your posts by the way.
On sleeping under the desks, I haven't seen that but maybe at Ford or Chrysler.

[Colvindesign]

Great thread Kachi, I've contemplated this as well, and have thought that FFR should offer a package on each chassis for people who want to design and build their own body. Then there is of course the time and money to build your own body. Perhaps the best DIY method I've seen is to build a CAD model, slice it into layers and build a buck out of wood or foam slightly smaller and build up with clay or bondo depending on how much smaller.

In the late 40's through the 60's design houses like Pininfarina, Touring and so on used factory chassis' (which if you look at an early Ferrari Chassis is very fragile looking) which they would alter as needed by simply moving the small steel tubes to where they needed them and then building a wood buck which was used to form the aluminum skin. But looking at the FFR chassis pictures, I picture making my own body for each one of them, and I think it could perhaps launch a new era of coach built sports cars.

For example, here is a sketch I did for a Roadster chassis based sports car,

[kach22i]

If you are into automobile aerodynamics, these books scans will entertain you.

http://ecomodder.com/forum/member-ae...strations.html

member-aerohead-albums-book-illustrations-picture118-jarays-work-1922-tops-list-cd-0-15.jpg
member-aerohead-albums-book-illustrations-picture99-optimum-nose-configuration.jpg

[D2W]

Great post Olpro! I always find your industry insider information interesting. How many times during a five month design exercise do you second guess your design and wonder if you're making a monstrosity?

[kach22i]

I've decided to learn from the best.......................

http://ecomodder.com/forum/showthrea...-18754-19.html

[olpro]

http://www.amazon.com/H-Point-Fundam.../dp/1933492376
This book directly addresses the manikin and other packaging issues so I thought I would post it here, to bring this thread up to date.

[kach22i]

That 3-book package deal looks tempting.

It's about as much as I've spent recently on gloves, thick wool socks and sock liners getting ready for winter. Gotta keep warm.

[olpro]

I now have the "H-Point" book and it is excellent. I would recommend it to anyone who is interested in vehicle design.
One shortcoming is that there isn't a manikin provided in the book so you would have to obtain one (from SAE?) or scan one from the book, separate it into parts and work with it.
The book has lots of other info on engines, tire sizes, typical seating dimensions for reference, etc.

[kach22i]

I now have the "H-Point" book and it is excellent. I would recommend it to anyone who is interested in vehicle design.

I came very close to ordering the 3-book deal, put it in my shopping cart and had my credit card out. I chickened out, will be getting a cheap Blue-Ray player instead for the same amount of money (my old DVD player is acting up).

[olpro]

I came across this German company that provides automotive type modeling clay.
http://www.kolb-technology.com/en.html

http://www.chavant.com/chavant_ob/index.shtml
The second link is a main USA supplier of clay and clay tools.

[olpro]

Here are some pix from the College for Creative Studies senior show (Detroit), with their amazing model work. These seem to be mostly from a sponsored (Lincoln) project and, although the designs are rather bizarre, the models show what their students are capable of doing.
CCS and Art Center in Pasadena, CA are the two primary schools feeding designers into the US studios. Academy of Art University in San Francisco and Cleveland Institute of Art are also important sources of talent for the industry - although talented grads can come from many other places as well.

http://www.flickr.com/photos/sven_de...th/6517913733/

[kach22i]

http://www.flickr.com/photos/sven_de...th/6517913733/

Those are Tyler's pictures. He posts on ecomodder as Sven7. A good guy with some serious talent.

[carbon fiber]

alot to this. don't be fooled. even if you have the plug cut by computer, there is tons of design, details and the molds and parts to make. i'm planning on some serious body mods in the future(not a total redesign-heavily modded) and i'll be making parts in cf from molds using vacuum infusion. lots of hours. not that it can't be done, but it's not as easy as it sounds. gotta really want it for this amount of work.

[olpro]

http://www.the-blueprints.com/
A source for vector drawings on many cars, etc. Good reference site for body design.

[olpro]

.. another shot at the fabric bodied car…
The windshield surround, which would include the upper cowl/wiper mounts, is fiberglass.
The wheel wells including the visible flanges are also fiberglass.

Fab1DD.jpgFab1CC.jpg

[kach22i]

.. another shot at the fabric bodied car…

Looking real good.

Remind me, you went with the lower seat position, so this is only about 45" tall, right?

Are the rear wheels/tires slightly larger than the front?

[olpro]

OAH at the orange bars is 46” but a roof would have to be a little higher over the heads with this manikin position (about 9.5” heel to H-point). This is not the real low seating position.

Front tires are 225/40/18x8
Rears are 275/35/19x9.5 (I went to a 35 series on the much wider rear tires, to look right with the fronts)

[crash]

Funny this thread should come back up.

I am HIGHLY modifying an FFR GTM and recording EVERYTHING I am doing in high def video. I am basically going to document EXACTLY how to build an entire car. I have built roughly 6 cars from the ground up previously.

Here's some pics...

GTMR Cut Apart.jpgGTMR Nose Reconstruction.jpg

[olpro]

Crash, You're in San Diego? I have got to get by to your shop some time. Your project sounds fantastic.

Here is a side view on my fabric car.

fab1 copy.jpg

[kach22i]

On the fabric car I like the middle roof "T" bars.

With a windshield incline like that, I would think that it would help prevent the windshield from folding inward upon roll-over.

The car floor line with the slight curve up near the rear wheel does add something to the mix. I will have to study other cars I like and see if any of them incorporate similar features.

[olpro]

Here is a pix showing how the front and rear panels swing up. The front would provide access to fuel fill and a small storage compartment, the rear to the engine and transmission. I am hoping to not need more access (from the direct rear) than that.
The other image is just for fun. That is not my donor in the background.Fab1BB.jpgfab3.jpg

[kach22i]

FYI: I done some work on a car design (just for fun), go to the link to view, join the forum to comment.

http://ecomodder.com/forum/showthrea...tml#post290819

To quote myself:

The material (Monopan) will require a jig to be set up so that everything is square, but no full sized clay body required to cast a mold, and then to hand lay fiberglass or other complex composite methods using foam.

I'm pretty sure I can heat the Monopan to bend it like I did the Coroplast, but I think I can also get the Monopan glass layer unresined, curve it over a buck/form and vacuum bag it into the final form.

Like I said, I used this same thinking (Monopan) in building a hovercraft model (Coroplast - five feet long). The hovercraft would be a 50 foot long patrol hovercraft and is very stealth looking because of the faceted surfaces.

This car design is 12 inches longer in wheelbase than the FFR 818, and about 9 inches wider too. And it seats three, although the person in the back better be on the small side (2 + 1).

Photo gallery (minus and explanation):
http://s184.photobucket.com/albums/x...ransportation/

[olpro]

Kach, I like it!
Nonetheless I can't resist a reference to Stan Mott's famous Cyclops
http://sbiii.com/autopix/cyclops/cyciidwg.jpg

[kach22i]

Kach, I like it!
Nonetheless I can't resist a reference to Stan Mott's famous Cyclops
http://sbiii.com/autopix/cyclops/cyciidwg.jpg

That thing is "so me", you have no idea.

[Niburu]

Kach I would specifically design the rear for kids
ie; make sure car seats fit, I'm looking into retrofitting my 83 911 Targa to work with the latch system seats we have
and once they're in they'll match perfectly since they're black and tan Recaro child seats, which aren't as expesive as you would think

[Presto51]

Take a look at the Bailey Blade http://www.bxrmotors.com/index.php/page/4/?s=videos It has about seventy odd video and take you from start to finish.

Just more food for thought

Ron

[olpro]

Don't exactly know where to post this but this thread is as good as any.

http://www.thedesignacademy.com/news/
look about two thirds down the page at "staff additions"