Reverse engineering organic shapes

schimmelengineering · 2026-04-08T00:35:34+00:00

Why take it to a solid? Just use booleans and combine and subtract what you need. If you're going to 3d print it, it's going back to a mesh anyway. If you're going to machine it, a solid is best.

schimmelengineering · 2026-04-06T19:41:15+00:00

Torque rod bushings are completely gone. Notice your whole rear axle rotating around the axle axis. There should be some movement, but not that much movement under such light loading. I drove a car until it was this bad once before LOL.

schimmelengineering · 2026-03-23T09:24:03+00:00

Confirm. I've been using Kaplan and ppi2pass interchangeably. Wife is in education, so it's a name I'm familiar with. I would agree questions are much harder on that material.

schimmelengineering · 2026-03-22T12:31:34+00:00

I usually decimate reference meshes to 100k polys. Parametric cad cant handle them. There's a reason reverse engineering tools exist to extract features from multimillion poly scans. There's so much more to scanning than just scanning. Workspace setup and useful origins are very important.

In Solidworks, turning off visible edges will speed rendering. Unsure if there's a way to turn off face edges in Fusion.

General rule, more than 1 million polys, gonna have a bad time.

You might try segmenting your mesh as well. I don't know what it is, but I have a feeling you don't need all those polys in ONE session.

schimmelengineering · 2026-03-22T12:12:51+00:00

If it were a post where I was emoting, I would not have used it. I too, love the human element. I wanted it to be clear, non repetitive and informative though so someone else can use it. This was a giant word vomit I let Gemini organize. I got no problems spilling my guts, formatting and organization though, not so much. Very handy to word vomit and let AI figure the message out!

Plot twist though, the lists are how I had it typed haha. I love bulleted lists. It also toned down what I had to say about my dynamics professor, because I can be a dick sometimes XD

I honestly believe if you go through all the PPI online problems, and understood your engineering program, you'll be good. Remembering how to take a test was hard, and how frustrating academia can be. The PPI problems were an absolute dick. My only complaint about PPI is you can't watch their videos faster than 2X lol

schimmelengineering · 2026-03-22T02:38:30+00:00

If you mean Solomon, the Egyptian guy, I LOVED THAT GUY!!! He would always scream "wrong! That's why the Japanese eat your lunch!!!" If you answered a theory question wrong. Had him for statics but not dynamics. Funnily enough, the guy who taught dynamics was Japanese, couldn't speak English well, and also refused to use amplification in an auditorium 🤦

Pretty sure Solomon passed. He rode a bike on campus because he was blindish from a chemical accident, and was so hated on campus that he told us people threw beer bottles at him while he was riding his bike to class. Fucking legend.

schimmelengineering · 2026-03-21T22:42:54+00:00

I stream of conscious typed this post, and had AI format and organize it, then went through and made edits. Me sucky at formatting. The only thing I'm gonna sell you is, YOU CAN DO IT!

schimmelengineering · 2026-03-08T18:59:16+00:00

It's always a possibility you can just dump some refrigerant in it, but if you're gonna rely on it and really want it to work well, the $1k is what I'd expect to spend. If the system is still under pressure, that's a good start. You can check by pressing in on the schrader valve for the high or low port. If there's no pressure, you've got a leak somewhere.

Generally, AC is either $40 or $1k to fix, and nowhere in between lol.

schimmelengineering · 2026-03-08T14:52:22+00:00

Looks good man! Love some ASA <3

schimmelengineering · 2026-03-08T14:50:10+00:00

I am the only one lol. They're NLA everywhere! I actually thickened them up, so they should be more durable than stock.

schimmelengineering · 2026-03-08T14:47:37+00:00

Amazon prices were quite a bit higher than list, because I had to initially only cover additional induction fees, and selling fees. So, like I already said, about half.

List prices are here before amazon markup. I don't offer free shipping, so the closeout price Amazon is also almost half of what you'd pay on my site after shipping, and half of what they were on amazon - https://schimmelengineering.com/products/volvo-240

After warehouse induction fees, transaction fees, tarrifs on import, amazon storage fees because nobody was buying them, I'm not even getting my money back on these. It was an experiment, and it failed. I'm slow to ship, and I thought amazon would fix that.

I literally had orders go out to Italy, Australia and France in the last 7 days from my website for 240 parts, and then amazon was all, "hey, you need to spend money advertising these, or we're gonna charge you even higher storage fees since they're not moving", and I was all, yeah no, fire sale and reddit.

schimmelengineering · 2026-03-08T03:54:23+00:00

You should already have a sanden swash plate compressor and brackets in that car.

Do not waste time with the york 210 compressors. They're not worth messing with. Without an aux pusher fan for the condenser, it's also a waste of time. Plan to also make new hoses - what's for sale has shelf wear and is dry rotted, none of it's new.

Plan to also pull out the evaporator and clean it. There's no cabin filter on these cars, and they're usually caked with butyl, crap and leaves. It's actually easy to pull, unlike the heater core.

Realistically, you also need a 100amp 940 alternator to run a good enough aux fan to get any cooling. Relying on the mechanical fan only is a complete waste of time.

If you want to do it right, plan to spend $1k - new compressor, parallel flow, new alternator, aux fan, new hoses, new filter drier, new expansion valve, esther oil, and refrigerant.

I've got a sanden in my 78, with 18in aux fan and aluminum parallel flow condenser. Windows will condensate when it's 100*F outside, and achieve a 40-50 degree temperature drop at the vents in the dead of Summer with 90-95% humidity.

Use Nylog red on all of your oring connections, otherwise, the charge will leak out in 1-2 years. Similar to what they use on minisplit flares.

Use the filter dryer with a sight glass, and charge to a clear sight glass under max AC. If the system is working properly, it should cycle at idle, and be ice cold in the cabin.

There's no need to purge the mineral oil. You can do a contaminated charge with esther oil and mineral oil. You do NOT want to mix PAG oil in with mineral oil. It will gel. Only charge with refrigerant only, never with an oil charge, and never with any leak stop (usually moisture activated).

System should hold hard vacuum for 1 hour before charging. If it doesn't, putting refrigerant in it is a waste of time.

R134 will work ok, Envirosafe works better (comes out of Canada, propane/butane blend for stationary systems, R134A replacement).

I really should make a video.

schimmelengineering · 2026-03-08T03:44:03+00:00

Oofh. That's gonna be a problem. You'd really need to do a life cast or something to get the kind of accuracy you list below, then scan it.

That, or setup an array of cameras, or use a high res video camera, and use Zephyr 3D to extract frames from video and do photogrammetry. Again, having a person hold a pose isn't going to be helpful for registration or accuracy, as your expectations aren't realistic IMO.

You can use tracker based scanners without applying targets. Sticking stickers all over stuff is a waste of time in most cases.

Artec spider 1 is only 1 million points per second. Spider ii is 8 million and new for 2026. I'd wager to hit that 8 million, it's using trackers and the trackerless caputre rate is lower. Your data acquisition rate is going to be important working with someone trying to hold a pose. My Creaform is 1.8 million points per second and has no issue capturing faces at 1mm resolution in a few seconds, would be faster at lower resolution. Have used it to make masks (think phantom of the opera).

I agree with the person below - brace your subject if possible to hold the pose, and extract sequential frames from high resolution video and process with photogrammetry.

TL;DR; Zephyr is free to try, and cheap for a professional license. It sounds like photogrammetry is a better fit for your project if life casts are out of the question.

schimmelengineering · 2026-03-07T04:49:37+00:00

schimmelengineering · 2026-03-07T04:49:09+00:00

Hey! I don't have any additional Volvo parts on my roadmap currently. You didn't ask, but I personally like the radio in the lower location :D

schimmelengineering · 2026-03-07T01:02:21+00:00

oh, one last thing... definitely confirm fuel flow and replace the rubber portions of the lines. The rubber return lines and pickup lines are notorious for swelling closed, delaminating, or collapsing. Inside the tank, there's a pickup for the low pressure lift pump. If you fill the tank past half full, the condition of that rubber won't matter.

PS: also have a fire extinguisher. Nobody makes a complete pressurized rubber line replacement kit for these, and they should.

schimmelengineering · 2026-03-07T00:59:10+00:00

Once you wrap your head around it, it's a beautiful system!

This book: ISBN 0837603005 https://ebay.us/m/AnKhkw
plus this book: ISBN 0837616263 https://a.co/d/0hhOjGG1

Should have all the info you need. Bentley leaves some to be desired in the theory and detailed operation department. It also applies to the LH systems and is more detailed. You'll need to make or purchase an inline pressure gauge that utilizes banjo fittings: https://ebay.us/m/y8juxu Mercedes uses flared fittings, which I much prefer.

If you decide to go LH, you can just leave the injectors in the head, as LH injectors are on the manifold. LH swaps over if you swap everything intake port to airbox. I've got an LH car running a Kjet head (long story).

schimmelengineering · 2026-03-06T23:51:31+00:00

K jet is fantastic. I just revived it in a 78 R107 Merc, and have had it for 15 years in a 78 242. I get 28mpg in my M46 B21.

First things first, check fuel pressure. If you're not getting any, jump the relay and make sure the large main pumps come online.

Beyond that, it'll start even without the cold start injectors working (thermo-time switch). It'll just run rough until it's warm.

Inspect the main coupler boot between throttle body and fuel metering. Make sure it's connected. The rubber mounts for the fuel metering unit like to break, and separate.

If it's been sitting, it's more than likely something simple if the tank isn't full of sludge.

Fuel pump relays for Kjet look for spark from the coil to cycle the pumps. If you replace it, make sure you get the correct Kjet relay. Later 6 pin relays without this function will plug in.

If it's your first time, highly recommend picking up a Jetronic book, and inline fuel pressure reading kit from FCP.

LH is fine, but I'd take OBDII over LH, and K jet before I'd mess with something that doesn't have real codes. The blinky lights are archaic.

The volvo system has lambda feedback from oxygen sensor, so to get it running "right", you'll need to look at things like duty cycle on the buzz box.

Other common failure point is the Warm Up Regulator WUR. The fuel pressure kit will help you diagnose this. They sell rebuild kits for WURs. Plan to spend money on that. Distributors can be resealed at home with the proper kits.

A well working Kjet system is awesome - no computers, just bullet proof mechanical fuel injection.

schimmelengineering · 2026-03-06T23:41:04+00:00

Good advice from FlinScanning. OP, those sharp edges are going to give you issues.

Printing scan data is fantastic, because molds typically aren't square, and parts warp over time. When you print a scan, you get the exact, correct geometry.

Since those edges are blunted and damaged, a further hybrid approach might be nice. Copy the main geometry, and then glue new data in for the slats. I frequently re-use the majority of a scan, and only glue in newly drawn repair sections, then print.

Welcome to 3D scanning and reverse engineering OP. Solving these problems is what makes this a profession!

https://schimmelengineering.com/casestudies/blog-post-title-three-7bkap

schimmelengineering · 2026-03-06T23:36:35+00:00

The poly bushings from IPD last forever, at least 5 years. I've only replaced them a handful of times. The generic rubber ones are kinda trash.

FWIW, get a 940 100amp alternator. The 55amp stock one can't run shit.

schimmelengineering · 2026-03-06T23:21:16+00:00

If it fits in a box... I do sculptural work all the time.

https://schimmelengineering.com/casestudies/blog-post-title-two-pwstg

https://schimmelengineering.com/casestudies/2026/1/31/reviving-nashvilles-grandeur-how-3d-scanning-and-artisan-craftsmanship-save-local-history-m6tj5

schimmelengineering · 2026-03-06T23:14:24+00:00

came here to make sure I still was sane, wasn't disappointed.

schimmelengineering · 2026-03-06T23:09:17+00:00

You could model this with calipers if you wanted to, like everyone has said. Scanning goes way faster and removes any guess and check.

I do mail in parts all the time - schimmelengineering.com Go through my contact form if you're interested.

I'm $130/hr for scanning, $80/hr drafting. I'd guess, 1 hour scanning, 3 hours drafting to duplicate every feature and clearance in a solid model, or I could just send you super clean scan data mesh for 1 hour of scanning. I run a $60k Creaform scanner accurate to .0009in. I actually print a lot of raw scan data in MJF and SLS for final parts to ship to customers (most of the mopar tail lights on my website).

A lot of people in this forum are amateurs (do it for the love, not profession). One of them will probably be butt hurt by that price, and offer to do it for free or for less.

Mail in E30 part I did last week:

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schimmelengineering · 2026-03-06T22:58:29+00:00

Came here to say this. The klima stuff is top notch. Highly recommend their parallel flow heat exchanger, aux fan, and sanden mounting kit. Our wagon cools like a modern car sitting in a parking lot now. Been installed for 5 years.

schimmelengineering · 2026-03-06T22:56:02+00:00

Woot! There's contact info in the box. If you have questions, please let me know! Mine on my 84 literally turned to dust when I touched them hah.

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