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Need HELP with 3D printing


Menelaos

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Hey guys I'm searching for someone who can create a CAd file of the ejection seat of the F-104G GQ7A...in 1:18 scale. By shapeways they want 150+ Euros only for creating a simple form of the seat and over 300 for a detailed one...that's a realy expensive story...

 

So that would be a great thing if someone could do that job for less money. TNX in advance

 

f-104-starfighter-gq7a.jpg

Edited by Menelaos
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"So that would be a great thing if someone could do that job for less money. THX in advance"

Duh, sure would be great if someone would do all that very complicated work for a very low price.

​Obviously you have no idea at all how much work is involved in making that 3D drawing.  Not to speak of printing it in 3D.

I'm in agreement with you that it would be great if someone would do that for a reasonable price. Now you know why aftermarket items cost so much. The maker needs to get paid for all the time he put into the making the model parts.

Back in ye good olden days when a modeler needed a certain part he would scratch build it himself out of wood. That was when modelers  were making models, rather than just buying parts others made and gluing them together. 

 

On the other hand, if I wanted a certain part or even a complete model all I have to do is SCAN an accurate plastic model that exists in a smaller scale, Enlarge the part up to the scale one wants and then feed that electronic file into a 3D printer and produce the part. 

Simple but do you have any idea how much it costs? There is the cost of the computer (it is not a cheap unit I assure you), plus the software for scanning, plus the software for printing, plus the printer plus the incredible amount of time necessary to learn how to use these software programs  All this for what? A model of a seat? Spend many thousands of dollars and months of time just to make a place to park a 1/32 scale pilot's butt?

Yes you can hire a place to do the illegal scanning and the printing but try to find one that will run the risk of making an illegal copy of a model and then reproduce it so they can sell you the copied part for a few dollars?  Yes that may work if you are dealing with mainland China but they will expect to get lots of money from you for the service. 

That is why I prefer to whine. Indeed I have become an excellent whiner.   :crying: 

Or I can scratch build the part myself. Gee, what a novel idea.

ssculptor

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Those prices sound great, take it!

It would take a lot of hours to create that artwork. CAD designers are skillled workers. How much do you pay a skilled worker, plumber, carpenter, car mechanic, per hour? Why should a skiled CAD designer spend his/her own valuable time doing this for less?

As Tim said, if you do not want to pay, learn how to do it yourself. You don't have the time to learn? Fine! Then we circle back to paying someone else to spend their time. I think that at least 20-30 hours of work are needed to get a decent design, even more hours for a great design, for that ejection seat. Charging 150 - 300 euros for that puts the per-hour fee close to minimum wage. Take it!

Radu

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On the other hand, if I wanted a certain part or even a complete model all I have to do is SCAN an accurate plastic model that exists in a smaller scale, Enlarge the part up to the scale one wants and then feed that electronic file into a 3D printer and produce the part.

 

I'm not entirely sure, I suspect that there would be copyright issues in doing that. Makes me wonder about those SAC parts made by copying kit parts

 

Richard

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I can only agree with what others are saying here.  CAD modelling can in theory be very easy - a few mouseclicks and you have a basic shape.  However, creating the multitude of shapes to make up an ejection seat and making them look accurate is a lot of work.  Even with many dimensions to work from as one can't have taken all necessary measurements, there will always be some dimensions that will have to be guessed or estimated, and then one needs to check that the shapes and proportions look right.  And then add a lot of detail that will be necessary to make a suitably busy appearance in such a large scale.  In any case, CAD systems will easily generate mechanical shapes like the seat frame, but you will need a program like Z-Brush to create the soft, organic shapes of the seatbelts and cushions.  For 300 Euros it may be worth investing in a simple CAD package which will allow you to create designs of your own.  Give a man a fish vs teaching him to fish and all that...

 

Jens

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I'm not entirely sure, I suspect that there would be copyright issues in doing that. Makes me wonder about those SAC parts made by copying kit parts

 

Richard

Of course there are copyright issues. But no one is going to chase you down and spend much money prosecuting you if you make one copy for your private model. Not worth the effort. But to sell copies to other people means you have crossed the line and are openly engaging in a copyright violation.  

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I think there's a bit of a misconception of what 3D scanning provides [ perhaps too much faith in the Airfix sales pitches ] There are two types of 3D file in CAD :-Mesh and Polysurface. Polysurface is the clean 3D surfaces you create in CAD which have to be very crisp and accurate to print or machine from and a Mesh is a 3D file which is made from very small triangular surfaces.

The mesh is the 3D file you get from a scan and it's manipulation in CAD is limited and so for say a figure you could automatically repair the holes which isn't always how you want it and then scale and print from it. 

Scanning a kit would be fraught with difficulties because if you scanned the part it would need a thickness and chances are the edges wouldn't be very crisp and once scaled up would look awful.

Scanning for model aircraft is mainly used as a drawing aid where you can drop lines on a 3D Mesh scan and then redraw that line because it will have a million points on that line because you've dropped it on a surface with a million triangles on! The more points on a CAD object the more difficult it is to manipulate the surface you've created from the 2D lines such as offsetting the surface for thickness or trimming etc.

That seat by the way which I'm about to draw a similar one I reckon is going to take me about a week or more and after 30 years of CAD I'm fast...

The usual problems are going to be drawings i.e there aren't any.

 

Graham

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Of course there are copyright issues. But no one is going to chase you down and spend much money prosecuting you if you make one copy for your private model. Not worth the effort. But to sell copies to other people means you have crossed the line and are openly engaging in a copyright violation.  

 

It was the second bit that I had in mind.

 

You're right about the first bit - not that I would want a scaled up grainy 3D scanned version. As you say, what's the point?

 

Having said that, I do tend to model things no-one is going to make kits for in any scale. I'm tempted by this beauty:

 

COWBiplane-No10.jpg

 

I quite like the guy with the pipe

 

Richard

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I think there's a bit of a misconception of what 3D scanning provides [ perhaps too much faith in the Airfix sales pitches ] There are two types of 3D file in CAD :-Mesh and Polysurface. Polysurface is the clean 3D surfaces you create in CAD which have to be very crisp and accurate to print or machine from and a Mesh is a 3D file which is made from very small triangular surfaces.

The mesh is the 3D file you get from a scan and it's manipulation in CAD is limited and so for say a figure you could automatically repair the holes which isn't always how you want it and then scale and print from it. 

Scanning a kit would be fraught with difficulties because if you scanned the part it would need a thickness and chances are the edges wouldn't be very crisp and once scaled up would look awful.

Scanning for model aircraft is mainly used as a drawing aid where you can drop lines on a 3D Mesh scan and then redraw that line because it will have a million points on that line because you've dropped it on a surface with a million triangles on! The more points on a CAD object the more difficult it is to manipulate the surface you've created from the 2D lines such as offsetting the surface for thickness or trimming etc.

That seat by the way which I'm about to draw a similar one I reckon is going to take me about a week or more and after 30 years of CAD I'm fast...

The usual problems are going to be drawings i.e there aren't any.

 

Graham

 

Good post Graham. I spent about 20 years around all aspects of CAD when 3D scanning and printing was new. The mesh in those days came from coordinate measuring machines...

 

Richard

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Yeah, there is a lot of "chat" on the Internet about the double-magic of scanning and 3d printing. Some people think it is the shrink-o-ray of the fifties magazines. That will never happen. And it will never ever be cheap.

I do a fair bit of CAD design these days and I worked with 3d scans. At the very most a scan will only serve as a basis to create a part, no more different than working with 3-view drawings. The only difference is that 3-view drawings can sometimes be wrong whereas a scan of a real part is more accurate.

However, designing models is seldom about scaling parts down very very accurately. Every single model part is a compromise, dictated by the limitations of the tooling, be it 3d printer or injection mould. Almost all details, rivets, cables, instrument bezels, anything, need to be made within the minimum tooling requirements, minimum material thickness. An experienced designer will be able to create parts that can actually be produced with the available tools. For example there is no point in making an accurate-to-scale 0.05mm rivet when the smallest rivet that a 3d printer can make is 0.1mm but you will need to make it at least (if not more than) 0.15 mm to see it.

I'm afraid the only way to get a 3d printed scale model of that that seat is by creating it in CAD. Alternatively you can scratch-build it the old fashioned way.

Radu

Edited by Radub
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I'm still in the old school camp where I can't believe they are printing actual items from a computer !  That in itself blows me away, and I saw a thing the other day on the news where they are 3D printing new hearts and bits and pieces to put in us humans when our own  OEM stuff breaks down... now THAT is incredible bit of CAD and 3D stuff....... goes well beyond scale model parts....... pretty cool I'd say..

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At work we have used a company to scan a vehicle chassis that is then used to create surfaces, and the equipment is high resolution scanners that is accurate to less than 0.2 mm over 6 metres.  The problem with scanners is that they can only register what it can see - line of sight, so there will still be a fair amount of guesswork when it comes to interpreting the scans and build up a more complete CAD model.  To create surfaces that can be converted to a CAD format, programs that do that are used.  This sort of equipment is not cheap - £five figures before the comma, approaching six...  Yes, one could scan a seat, convert the files to a format that can then be 3D printed, but that's not going to be cheap...

 

Jens

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