Hello from NorCal

[Muiren]

I'm a 67 years old semi-retiree with a career background in engineering, IT, project management. I've had my motorcycle rating since my teens and frequently bikepacking and camped for mental health until very recently.

Like many people, I've dreamed of a GMC motorhome since they were first introduced. After spending almost a year watching hundreds of hours of other people's projects and reading their blogs, I've decided my goal is to first outfit a purpose-rebuilt workshop in preparation for a frame-off battery EV with range-extender restomod that remains aesthetically faithful to original design, ideally using a bare bone TransMode as the donor vehicle. There have been a lot of imaginative restomods, but in my opinion, they no longer look or function like the GMC design team concept.

This brings me to my first question bearing on my plan, Where can I buy GMC Motorhome Technical Drawings in CAD format? I followed the forum link to the GMC licensed 3D images of the GMC Motorhome sold on Turbosquid, but haven't found any precision digital technical drawings for sale or free to the GMC community.

I believe I heard the original body molds are in safekeeping in one video, but has anyone taken the original blueprints, like those scanned by Boyd Mooney, and recreated them in CAD or at least some editable vector format?

 

[JSanford]

Welcome!

Sounds like a very ambitious project!

 

[kidjedi]

I have not seen any drawings like this available. Most mods and "upgrades" I've seen are still being done by putting tape (or laser) to points on the vehicle. Right now I think creating CAD drawings with Solidworks or Inventor could be realistic by using a scanner on the chassis and shell and interior layout, but cleaning up that scanned mesh is a major endeavor. Unless there is tech I'm not aware of, making that happen for mechanicals would be a nearly impossible undertaking at this point in time. If someone is in the process of doing the former (scanning/converting chassis and shell), hopefully they'll start a thread, and maybe some of us can pitch in to distribute the load. Alternatively, if there were access to factory schematics and drawings, we'd be ahead of the game.

 

[Muiren]

I have not seen any drawings like this available. Most mods and "upgrades" I've seen are still being done by putting tape (or laser) to points on the vehicle. Right now I think creating CAD drawings with Solidworks or Inventor could be realistic by using a scanner on the chassis and shell and interior layout, but cleaning up that scanned mesh is a major endeavor. Unless there is tech I'm not aware of, making that happen for mechanicals would be a nearly impossible undertaking at this point in time. If someone is in the process of doing the former (scanning/converting chassis and shell), hopefully they'll start a thread, and maybe some of us can pitch in to distribute the load. Alternatively, if there were access to factory schematics and drawings, we'd be ahead of the game.

My vision is to create basic reference schematic in CAD from existing scanned paper drawings, guided by reliable documentation.

I have several years experience in 2D and 3D scanning, and plan to a combination of industry standard laser and the new generation of photogrammetry using the KIRI Engine to capture fine details.

Though this is for my own use, my goals include my non-profit to continue the mission and digitizing the rest of the product family, and make it accessible for registered community members via an online database.

The digitization part of the project isn't really as ambitious as it may sound to, and I believe it has historic merit while being of long term value to current community members, and future generations who may be inspired restore or build accurate reproductions.

It's not that far fetched, since there are several classic cars like 1960s era Mustangs or the VW Bug that can be recreated from new parts.

Anyway, thanks everyone for the welcome, and I'll track down the appropriate section of the forum to start a thread on the CAD subject later on.

 

[pvfjr]

One word of caution on the 3D scanning:
Be careful which coach you use as your reference. Due to the phenomena of "middle age spread" and "chipmunk cheeks", these coaches tend to differ from one another a decent amount. A model constructed to fit one coach may not fit another very well.

 

[Muiren]

One word of caution on the 3D scanning:
Be careful which coach you use as your reference. Due to the phenomena of "middle age spread" and "chipmunk cheeks", these coaches tend to differ from one another a decent amount. A model constructed to fit one coach may not fit another very well.

Over the past week, I watched several videos on structural deformation, including Jim Bounds' “Chipmunk Cheeks”, because of vehicle age and wear, original design, and assembly line technology and execution of the period.

As mentioned, scanning will only be used to fill in detail work.

There already exists adequate specifications from primary sources and owner community sources to inform and render accurate mechanical CAD of the main structural components.

Despite being dimensionally accurate, many scans will just serve as references and for producing presentation walk-throughs. I can draw faster than it takes to clean up most scans, and clients are billed for my time.

Example: The attached is a rasterized copy of a vector 3D image recreated from scanned GMC badging and the EV from a Hummer using KIRI Engine (Gaussian Splatting). This will be produced with a 3D resin printer, and if I can make the numbers work, I will be accepting commissions as reward for monetary donations to the project.

A 3D scan as a reference image, is a way faster and more precise workflow than guesstimating with 2D photos from different angles. Tutorials accompanying the CAD database, I propose, will make use of downloadable and printable EPUB format with both static and animated SVG for procedural step-by-steps. 3D walk-throughs will be created with Gaussian splatting tech conversions within Blender.

Nothing expensive or bleeding-edge, only just proven, cost-effective, easily accessible industry standard technologies. FreeCAD, Blender, and KiCAD for electronics, will be the primary platforms used to remove barriers of access for community members interested in participating.

They have professional grade features adequate for the goals of the mission, and though many valuable plugins are paid ― they are each free and open-source with active, thriving development and user communities.

 

[pvfjr]

Sounds neat, I'll keep an eye out for what you come up with.

I lost my Solidworks access 10 years ago and tried to continue onward with open source options for home projects. That meant FreeCAD since I use Linux, but I just switched from FreeCAD to OnShape with more enthusiasm than I could ever convey. It's pretty neat.

 

[Muiren]

Sounds neat, I'll keep an eye out for what you come up with.

I lost my Solidworks access 10 years ago and tried to continue onward with open source options for home projects. That meant FreeCAD since I use Linux, but I just switched from FreeCAD to OnShape with more enthusiasm than I could ever convey. It's pretty neat.

To start with, my perspective is informed by starting to learn laboratory protocols, experiment design, and mechanical drafting in the late 1960s and early 1970s as a kid under the mentorship of Dr George Sperti, and being an early adopter of CAD systems in the late 1970s at U.C.

OnShape is a walled garden or closed ecosystem, a deliberately hobbled lead-loss freemium product with Ui and workflow intended to emotionally comfort users acclimatized to massively expensive corporate platforms and work environments. By design, OnShape free version does not compete with its own $1,500 per annum product.

My commitment is serving the common welfare of the GMC Motorhome community, not hyper-individualistic self-gratification. Within our mission parameters, OnShape, and similar "free" commercial products, are not really free, and have no objective advantage over the open-source FreeCAD ecosystem, which is among the most widely used software platforms by DIY/Hacker/MakerSpace communities worldwide, and includes FEM (Finite Element Method) and FEA (Finite Element Analysis).

I consider FED/FEA and other design tools like OpenRadioss essential to the ongoing study of aging GMC chassis components, with an eye to designing both safe and reliable repairs or modifications. FreeCAD has many other practical features, and important to my proposal, the ability to customize it with the support of its development and user community, something literally impossible with OnShape and other commercial products.

 

[RF_Burns]

I believe I heard the original body molds are in safekeeping in one video, but has anyone taken the original blueprints, like those scanned by Boyd Mooney, and recreated them in CAD or at least some editable vector format?

Jim Bounds solicited funds several years ago to obtain the original SMC molds. He then had them scanned and from my understanding, sold the original molds for scrap. He hasn't mentioned what happened to those files or what he intends to do with them.

Maybe someone who "donated" funds to this endeavor has more info.

 

[Muiren]

Jim Bounds solicited funds several years ago to obtain the original SMC molds. He then had them scanned and from my understanding, sold the original molds for scrap. He hasn't mentioned what happened to those files or what he intends to do with them.

Maybe someone who "donated" funds to this endeavor has more info.

Thanks for the 411. I joined Jim Bounds' Patreon, both in tribute to he and his team's ongoing contributions to the community, and to ask that kind of question. Although I'm interested in CAD files of the body parts, my priority though, is to first address the GMC rolling chassis, rebuilding that with modifications, and then, and only then, marry it to a refurbished body, ideally a 26' 1975 or 1976 plain-vanilla TransMode donor, so I don't commit sacrilege, tearing apart those awesome retro internal appointments I think should instead be lovingly restored.

Now that jacked up 6×6 GMC motorhome I see posted everywhere online, probably has its audience, but I love and study magic and illusion, inventing things that look completely mundane, “normal”, but then surprise you by doing the remarkable. My visions is a 6×6 in-hub electric drive and steering, that is completely stealth, a battery electric with a multi-fuel, high output, generator inverter, range extender system that effectively reduces the size and weight of the battery packs.

As you experienced owners know, the stock GMC frame and body is very flexible, too much so for what I have in mind, the torque of an electric all-wheel drive would tear the vehicle apart on the road. I need to buy an existing GMC chassis in good condition, so I can take precision measurements of the frame, mounting points, bogie assemblies, and steering geometry.

Confirm those measurements against published specifications, followed by the exacting work of designing, testing, building prototype modifications that provide the strength to accommodate the drive, active suspension, and steering system require, without changing the vintage beauty of the GMC look, road stance, and ride.

 

[RickHaugh]

I'm a 67 years old semi-retiree with a career background in engineering, IT, project management. I've had my motorcycle rating since my teens and frequently bikepacking and camped for mental health until very recently.

Like many people, I've dreamed of a GMC motorhome since they were first introduced. After spending almost a year watching hundreds of hours of other people's projects and reading their blogs, I've decided my goal is to first outfit a purpose-rebuilt workshop in preparation for a frame-off battery EV with range-extender restomod that remains aesthetically faithful to original design, ideally using a bare bone TransMode as the donor vehicle. There have been a lot of imaginative restomods, but in my opinion, they no longer look or function like the GMC design team concept.

This brings me to my first question bearing on my plan, Where can I buy GMC Motorhome Technical Drawings in CAD format? I followed the forum link to the GMC licensed 3D images of the GMC Motorhome sold on Turbosquid, but haven't found any precision digital technical drawings for sale or free to the GMC community.

I believe I heard the original body molds are in safekeeping in one video, but has anyone taken the original blueprints, like those scanned by Boyd Mooney, and recreated them in CAD or at least some editable vector format?

I’m building a modern chassis for the GMC.
I have a post on this forum about it.

Rick Michelhaugh
Give me a call 865-456-1118

 

[Muiren]

I’m building a modern chassis for the GMC.
I have a post on this forum about it.

Rick Michelhaugh
Give me a call 865-456-1118

Found your post and studying your notes.
Absolutely outstanding work!
I hope you've made progress in mending and feel refreshed enough to resume your project with the new year, so we have something positive to look forward to. I found your strategy for the brakes fascinating, particularly the choice to retain the 4×4 brake configuration, only installing a set on the rear bogie wheels to “eliminate the pole-vaulting of the middle wheels under hard braking”.

 

[RickHaugh]

Found your post and studying your notes.
Absolutely outstanding work!
I hope you've made progress in mending and feel refreshed enough to resume your project with the new year, so we have something positive to look forward to. I found your strategy for the brakes fascinating, particularly the choice to retain the 4×4 brake configuration, only installing a set on the rear bogie wheels to “eliminate the pole-vaulting of the middle wheels under hard braking”.

Text your email address to me. I’ve got more to tell you.

 

[Muiren]

Text your email address to me. I’ve got more to tell you.

This motorhome restomod is for me a recreational side project to enable travel and recreation. I will probably raise funds from grants and sales of my crafts and arts, but nothing that involves soliciting funds from the GMC motorhome owner community.

More important, and unfortunately more stressful, is my project of building a scale model lab and demonstrator of a transportation oriented community using software and hardware rooted in the ArduPilot ecosystem.

TınyMaker.Space™
https://tinymaker.space
https://longspeir.com
muiren@tinymaker.space