[Amapi] - Mercedes Aero Engines - Polyloop

PatrickDemski · 11th January 2008, 07:37

I am working on a project to model a series of WWI aero engines made by Mercedes in Germany. I decided to use Amapi Pro 7.52 and have just completed the first major construction, the cylinder. Here's a picture of it --

And here is the cylinder duplicated to show what the top-end of one of these engines will look like --

I'm very pleased with progress so far; the intention is to continue modeling in Amapi and then import the parts into Carrara 6 for assembly and rendering.

I have a question for the more experienced artists here. You can see that the cylinder is a basic hull with different features protruding from it. This hull is a Gordon surface. The real hull is welded steel stampings and forms a water jacket over a cast steel piston cylinder. So anything protruding from the hull has a weld seam at the point where it breaks the surface of the hull. I've tried to model those weld seams here.

Most of the time it's impossible to form the weld seam BREP from a chamfer -- the geometry of the curving break line is too convoluted. So I cut the surface of the hull with a cylindrical volume, then did a double sweep from the cut hole to a terminating curve. The resulting weld seam BREP was then welded to it's corresponding part. Overall, this was time consuming but worked well.

However, I keep thinking that there must be a way to project a curve onto the surface of the hull, grab it, and pull it out to form the protruding feature. Then the hull, weld seam and protrusion would be a single part with smoother transitions. Does anyone know if this is a possible construction technique? How would I do it in Amapi?

BTW Thomas, Amapi is the best!!!

It is a truly great modeling tool and perfectly suited to this kind of project. I enjoy using it every time!!! I'm so used to the interface that when I go into Carrara I'm always a bit lost since I keep trying to use Amapi key strokes and mouse moves -- and they don't work. A wonderful product.

Hugo · 11th January 2008, 10:02

Nice start Patrick, it's great to see some nice Nurbs modeling here ! Can't wait to see what's coming next.

PatrickDemski · 11th January 2008, 15:20

Thank you Hugo - I'm going to start setting up in C6 and add a few details to what I already have. Then the next big pieces are the crankcase and rocker boxes. Once those are done, the rest of the project is all downhill.

Pete Exxtreme · 11th January 2008, 16:28

Nice beginning. I'm longing for the rest and the texturing/rendering

PatrickDemski · 12th January 2008, 04:24

More will come soon Pete - and I really like your Tiger PzKpfw VI!!! Some phenomenal modeling

-- I hope that when I finally get to the point of wrapping aeroplanes around my engines they turn out as good!

3webjam · 1st February 2008, 13:48

Ah, Amapi... Have it on my PC as well, but decided to start first with Hexagon...
This sure does look good!
Jacqueline

shoeach · 6th February 2008, 12:06

Good start, Patric.

Quote:

Originally Posted by PatrickDemski

and I really like your Tiger PzKpfw VI!!! Some phenomenal modeling

I 100% agree with you.
“How to model Tiger PzKpfw VI” tutorial by Pete is my big dream.

Syuichi

RolandD6 · 27th February 2008, 22:27

Looks good Patrick, I also am keen to see your finished model.

In 1998 I did a similar project in Autocad (2D) on the Mercedes engine. From that project I produced a book of drawings for the engine (ISBN: 0-646-35145-1) and built a 1/5 scale model; see http://www.wwi-models.org/Images/Butler/index.html.

The model got no further than the images on the web site above, although I plan further development. More work is needed on the cylinder jackets and I have not yet made the patterns for the inlet manifold and carburettor. At present there is no need for me to create a crank case for the 1/5 scale model because the plan was to develop a replica engine to fit into a flying model. Part of the future development is to achieve some serious weight saving.

I also intend to create a 3D version to fit into my 3D airplanes (Pfalz D.IIIa will be first) and that project is likely to happen much sooner than an updated 1/5 scale model.

Regards

Paul

PatrickDemski · 29th February 2008, 01:47

Hi Paul, I have your book in my library

and have downloaded all of the photos that you've posted at WWI Models -- the ones from Trelour Annex at the AWM are especially useful because you took a number of detail closeups that most people overlook. Everyone takes sideview shots of the whole engine from six feet away; no one bothers to take pictures of the primer petcock from two inches away and a few different angles so that you can understand how it's shaped and assembled. Thanks much! I really needed some of those pictures. I've been unable to find a Mercedes D-series engine in Southern California that I can examine & photograph.

I'm actually building three different versions of the engine simultaneously since there are so many similarities between them.

The first version is the Mercedes D.III with the rocker arms protruding from the sides of the rocker boxes. This one saw wide use in the early B-series planes, and the early Alb and Pfalz scouts. It has a couple of variations in the water cooling plumbing depending on the plane and the radiator used; I've got the details for most of these but it took a long time to figure out how the rocker boxes and cam tube were shaped. I think I've got it worked out & am going to start modeling it next, after I finish up a few othe things.

The second version is the Mercedes D.IIIa, the subject of your book. It has the final-form valve train with the front-mounted rocker arms, and the heated intake manifold.

The third verison is the Mercedes D.IV, the 8-cylinder version used in the Alb C.V and LVG C.IV. Quite a rarity, but it has much commonality with the D.III version so it's not that much more work to do. I want to eventually do both the Alb and the LVG as 3D models.

I need to post some updated renders here; I've been working on detailing the cylinders with all the add-on parts like spark plugs and valve springs, and also doing the UV mapping in UVMapper Pro. I'll post pics of this work as soon as I can put it together in Carrara and do some renders.

BTW, I really like the 1/5 scale model you've been working on. My brother is a mechanical engineer & we've talked about exporting my 3D work as STL files so physical shapes can be produced on a prototyping 3D printer. I may do this after I've got the engines complete for rendering -- by the time I get to this stage, the 3D printing technology will probably be cheap enough to set up in a garage or workshop.

RolandD6 · 29th February 2008, 04:05

Quote:

Originally Posted by PatrickDemski

Hi Paul, I have your book in my library

and have downloaded all of the photos that you've posted at WWI Models -- the ones from Trelour Annex at the AWM are especially useful because you took a number of detail closeups that most people overlook. Everyone takes sideview shots of the whole engine from six feet away; no one bothers to take pictures of the primer petcock from two inches away and a few different angles so that you can understand how it's shaped and assembled. Thanks much! I really needed some of those pictures. I've been unable to find a Mercedes D-series engine in Southern California that I can examine & photograph...

You are welcome. I am glad to hear that my contributions to this particular interest have been useful. Also since you have visited the WWI Models web site you would have noticed my comments about errors in my drawings.

Regarding an engine to look at, where has the Champlin Museum Pfalz D.XII gone to after it was sold? There were various people around your part of the world who were building replica WW1 airplanes in the past. It may be worth your while to look up the civil aviation register. Just be aware that many replica airplanes have an inverted Ranger engine, eg. the Albatros D.Va at Old Rhinebeck Aerodrome, New York state

Quote:

I'm actually building three different versions of the engine simultaneously since there are so many similarities between them...

They will keep you occupied for a while.

Quote:

I need to post some updated renders here; I've been working on detailing the cylinders with all the add-on parts like spark plugs and valve springs, and also doing the UV mapping in UVMapper Pro. I'll post pics of this work as soon as I can put it together in Carrara and do some renders.

Love to see them.

Quote:

BTW, I really like the 1/5 scale model you've been working on.

Thank you. I made patterns from materials at hand, eg. steel, aluminum, plastic etc.; then silicon rubber molds, then cast in urethane plastic.

Quote:

My brother is a mechanical engineer..

So am I but most of my working life was involved in writing various types of documentation.

Quote:

... we've talked about exporting my 3D work as STL files so physical shapes can be produced on a prototyping 3D printer. I may do this after I've got the engines complete for rendering -- by the time I get to this stage, the 3D printing technology will probably be cheap enough to set up in a garage or workshop.

TurboCad will also export to STL but I am uncertain about the issue of 'holes' in the model surface. Apparently this is an issue with the 3D printing process. Often the people who produce the models have to fix a customers STL files beforehand. There was a feature article about this topic in '3D World The magazine for 3D Artists, Issue 97, December 2007'. You may be able to find a copy. It was still on the news stands here last time I looked a few weeks ago. Failing that, back issues are available through the publishers web site http://www.3dworldmag.com/

3d printing is not cheap, around US$250+ per item last time I looked.

Paul

PatrickDemski · 29th February 2008, 06:30

Quote:

Regarding an engine to look at, where has the Champlin Museum Pfalz D.XII gone to after it was sold?

The Champlin Pfalz went to the Museum of Flight in Seattle, WA.

Quote:

TurboCad will also export to STL but I am uncertain about the issue of 'holes' in the model surface. Apparently this is an issue with the 3D printing process. Often the people who produce the models have to fix a customers STL files beforehand. There was a feature article about this topic in '3D World The magazine for 3D Artists, Issue 97, December 2007'. You may be able to find a copy. It was still on the news stands here last time I looked a few weeks ago. Failing that, back issues are available through the publishers web site http://www.3dworldmag.com/

3d printing is not cheap, around US$250+ per item last time I looked.

I'll have to get that copy of 3D World. My impression of 3D printing is that it's still immature technology -- can by done, but pricey and requiring specialized expertise. In another 3 years, it'll be much improved and in 5 it will be a consumer technology.

RolandD6 · 29th February 2008, 06:43

Patrick

You may like to look at this URL from time to time.

http://www.fabathome.org/wiki/index.php?title=Main_Page

Paul

11th January 2008, 07:37	#1 (permalink)
PatrickDemski Vertex Join Date: Jul 2005 Location: Southern California Posts: 9	[Amapi] - Mercedes Aero Engines I am working on a project to model a series of WWI aero engines made by Mercedes in Germany. I decided to use Amapi Pro 7.52 and have just completed the first major construction, the cylinder. Here's a picture of it -- And here is the cylinder duplicated to show what the top-end of one of these engines will look like -- I'm very pleased with progress so far; the intention is to continue modeling in Amapi and then import the parts into Carrara 6 for assembly and rendering. I have a question for the more experienced artists here. You can see that the cylinder is a basic hull with different features protruding from it. This hull is a Gordon surface. The real hull is welded steel stampings and forms a water jacket over a cast steel piston cylinder. So anything protruding from the hull has a weld seam at the point where it breaks the surface of the hull. I've tried to model those weld seams here. Most of the time it's impossible to form the weld seam BREP from a chamfer -- the geometry of the curving break line is too convoluted. So I cut the surface of the hull with a cylindrical volume, then did a double sweep from the cut hole to a terminating curve. The resulting weld seam BREP was then welded to it's corresponding part. Overall, this was time consuming but worked well. However, I keep thinking that there must be a way to project a curve onto the surface of the hull, grab it, and pull it out to form the protruding feature. Then the hull, weld seam and protrusion would be a single part with smoother transitions. Does anyone know if this is a possible construction technique? How would I do it in Amapi? BTW Thomas, Amapi is the best!!! It is a truly great modeling tool and perfectly suited to this kind of project. I enjoy using it every time!!! I'm so used to the interface that when I go into Carrara I'm always a bit lost since I keep trying to use Amapi key strokes and mouse moves -- and they don't work. A wonderful product. Attached Thumbnails Last edited by PatrickDemski; 11th January 2008 at 15:38. Reason: Added attachments

11th January 2008, 10:02	#2 (permalink)
Hugo Rhymes with Hell. Join Date: Jun 2003 Location: France Posts: 2,902	Nice start Patrick, it's great to see some nice Nurbs modeling here ! Can't wait to see what's coming next. __________________ WARNING: The following posts contain explicit content. By viewing them, you are making the following statement: I am viewing explicit content.

11th January 2008, 16:28	#4 (permalink)
Pete Exxtreme Lick it up Join Date: Jun 2005 Location: Thonon/France Posts: 4,620	Nice beginning. I'm longing for the rest and the texturing/rendering __________________ Toute faute de frappe ou erreur de syntaxe sont dues a un clavier rebelle à toute forme d'autorité. LightWave 9 \| Hexagon 2 My gallery

29th February 2008, 06:43	#12 (permalink)
RolandD6 Vertex Join Date: Feb 2008 Location: Melbourne, Australia Posts: 9	3D Printers @ home Patrick You may like to look at this URL from time to time. http://www.fabathome.org/wiki/index.php?title=Main_Page Paul

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11th January 2008, 15:20	#3 (permalink)
PatrickDemski Vertex Join Date: Jul 2005 Location: Southern California Posts: 9	Thank you Hugo - I'm going to start setting up in C6 and add a few details to what I already have. Then the next big pieces are the crankcase and rocker boxes. Once those are done, the rest of the project is all downhill.

12th January 2008, 04:24	#5 (permalink)
PatrickDemski Vertex Join Date: Jul 2005 Location: Southern California Posts: 9	More will come soon Pete - and I really like your Tiger PzKpfw VI!!! Some phenomenal modeling -- I hope that when I finally get to the point of wrapping aeroplanes around my engines they turn out as good!

1st February 2008, 13:48	#6 (permalink)
3webjam Extrusion Join Date: Jan 2008 Location: Holland Posts: 167	Ah, Amapi... Have it on my PC as well, but decided to start first with Hexagon... This sure does look good! Jacqueline

27th February 2008, 22:27	#8 (permalink)
RolandD6 Vertex Join Date: Feb 2008 Location: Melbourne, Australia Posts: 9	Looks good Patrick, I also am keen to see your finished model. In 1998 I did a similar project in Autocad (2D) on the Mercedes engine. From that project I produced a book of drawings for the engine (ISBN: 0-646-35145-1) and built a 1/5 scale model; see http://www.wwi-models.org/Images/Butler/index.html. The model got no further than the images on the web site above, although I plan further development. More work is needed on the cylinder jackets and I have not yet made the patterns for the inlet manifold and carburettor. At present there is no need for me to create a crank case for the 1/5 scale model because the plan was to develop a replica engine to fit into a flying model. Part of the future development is to achieve some serious weight saving. I also intend to create a 3D version to fit into my 3D airplanes (Pfalz D.IIIa will be first) and that project is likely to happen much sooner than an updated 1/5 scale model. Regards Paul

29th February 2008, 01:47	#9 (permalink)
PatrickDemski Vertex Join Date: Jul 2005 Location: Southern California Posts: 9	Hi Paul, I have your book in my library and have downloaded all of the photos that you've posted at WWI Models -- the ones from Trelour Annex at the AWM are especially useful because you took a number of detail closeups that most people overlook. Everyone takes sideview shots of the whole engine from six feet away; no one bothers to take pictures of the primer petcock from two inches away and a few different angles so that you can understand how it's shaped and assembled. Thanks much! I really needed some of those pictures. I've been unable to find a Mercedes D-series engine in Southern California that I can examine & photograph. I'm actually building three different versions of the engine simultaneously since there are so many similarities between them. The first version is the Mercedes D.III with the rocker arms protruding from the sides of the rocker boxes. This one saw wide use in the early B-series planes, and the early Alb and Pfalz scouts. It has a couple of variations in the water cooling plumbing depending on the plane and the radiator used; I've got the details for most of these but it took a long time to figure out how the rocker boxes and cam tube were shaped. I think I've got it worked out & am going to start modeling it next, after I finish up a few othe things. The second version is the Mercedes D.IIIa, the subject of your book. It has the final-form valve train with the front-mounted rocker arms, and the heated intake manifold. The third verison is the Mercedes D.IV, the 8-cylinder version used in the Alb C.V and LVG C.IV. Quite a rarity, but it has much commonality with the D.III version so it's not that much more work to do. I want to eventually do both the Alb and the LVG as 3D models. I need to post some updated renders here; I've been working on detailing the cylinders with all the add-on parts like spark plugs and valve springs, and also doing the UV mapping in UVMapper Pro. I'll post pics of this work as soon as I can put it together in Carrara and do some renders. BTW, I really like the 1/5 scale model you've been working on. My brother is a mechanical engineer & we've talked about exporting my 3D work as STL files so physical shapes can be produced on a prototyping 3D printer. I may do this after I've got the engines complete for rendering -- by the time I get to this stage, the 3D printing technology will probably be cheap enough to set up in a garage or workshop.