Gnome 9N

[Bullethead 12]

I've been piddling around with the MS AI's motor for a while now, while I've been stuck on other things. Like right now, I'm stuck on the cockpit decking, so I got a fair amount done on the motor instead. It's not finished (still all separate objects) it's far enough along now to show off. As a real confidence boost, I checked it out on the airplane and guess what? It fit perfectly. The jugs even lined up with the slots in the bottom of the cowling. That made me feel a lot better about how I'm coming along here. <BR><BR>Special thanks to Shredward for the engine drawings! <IMG class=bbc_emoticon alt= src="http://forum.combatace.com/public/style_emoticons/default/drinks.gif">

Edited February 4, 2010 by Bullethead

[ConradB 0]

Lookin' good there BH! I've been toyin' around with the idea of getting at least the basics started on the Mercedes DIII 160hp, as it will help in getting the cowl refined on the forward fuselage. Almost need it really to get a proper visual perspective to finsish the forward part off.

[Bullethead 12]

Lookin' good there BH!

 

Thanks. I'm kinda proud of it. I had been worried about how I was going to arrange the cylinders radially because I couldn't figure out the array function. So what I ended up doing was putting the 1st one's pivot point at 0,0,0, clone, then rotate by 40^, repeat. Very simple.

 

I've been toyin' around with the idea of getting at least the basics started on the Mercedes DIII 160hp, as it will help in getting the cowl refined on the forward fuselage. Almost need it really to get a proper visual perspective to finsish the forward part off.

 

Yup, you sometimes need these detail parts before you can do the major structure. I was lucky I'd made the Vickers some time back for the M1c, so could slap them on the MS AI immediately when I needed them to work out the fuselage decking. And I was pleasantly surprised when they were exactly the right size. Until I put them together, I was never 100% sure I'd done the scaling correctly on either or both models .

 

BTW, you'll be needing to make some guns. I found an excellent site for dimensioned 3-view drawings of all the main WW1 MGs: http://www.arizonamodels.com/index.php/cPath/29_39. This is a model company and this link is to their page for scale MG kits. What you do is, you download the PDF assembly instructions. They've got the drawings in them.

[ConradB 0]

Yeah, I need a single spandau, and a parabellum. So I will zip over there. I was looking at their drawings for the Mercedes DII, but didn't look at their gun section. I was thimking of going over to the hobby store, and picking up a model of each for r/c planes, as they are detailed nicely. Especially the old Williams Bros vintage accessories for older style planes.

 

When building them as seperate objects, is there a way to keep them the same scale as the plane you're building? Or do you have to fiddle with stuff that way. Same for the engine too. As long as I have the unit scale the same for them, it should remain the same is that correct?

[Bullethead 12]

When building them as seperate objects, is there a way to keep them the same scale as the plane you're building? Or do you have to fiddle with stuff that way. Same for the engine too. As long as I have the unit scale the same for them, it should remain the same is that correct?

 

Yup, build everything 1:1 scale in Gmax. If the gun is 904mm long in real life, make it that long in Gmaz. If the plane is 8.34m long in real life, make it that long in Gmax. Then, when you merge the gun object into the airplane model file, both will be to the same scale.

[hairyspin 1]

I do like that! And when linked to prop_still it will spin at engine start like the Gnome engines did. You can also make a second one - which can be much simpler - to link to prop_blurred for the engine at running speed.

Now you need a propellor, so look up Uncle Milton's C162 tut series for a link to a tut for building one with a beautifully realistic twist to the blade.

[ConradB 0]

Hey BH, I started on the Merc DIII, just some simple stuff, but I need to get it to where I have the plumbing for the wing radiator installed accurately so I can finish forming the cowl and get the proper cut in it.

 

Here's a couple pics. This was just a couple hours foolin' with it to see what would arise from the meshes.

 

 

[Bullethead 12]

I do like that! And when linked to prop_still it will spin at engine start like the Gnome engines did. You can also make a second one - which can be much simpler - to link to prop_blurred for the engine at running speed.

 

Thanks!

 

Yup, that's the plan. The only way this engine will ever been seen is from external view, at very short range, with the motor off. The LOD versions will look like they're made out of Lego .

 

For the blurred one, I was going to take my detailed engine texture and circle-blur it, then apply it to a solid disk of about 11 total polys.

 

Now you need a propellor, so look up Uncle Milton's C162 tut series for a link to a tut for building one with a beautifully realistic twist to the blade.

 

That's my project for the next time I get stuck on something with the main plane. And once I do that, about the only such project left will be the cockpits, which I'm not really looking forward to.

 

Hey BH, I started on the Merc DIII

 

Looking nice! If you ever need a 150-160hp Gnome, I'll trade ya for it

[ConradB 0]

I don't mind sharin'. Once I'm done with it, I'll pop a copy over to ya' so you will at least have it on file. Never know, you may need one. Nice thing is, it's close enough to the 185 BMW engine, that with a few mods here and there, both can be had.

[Bullethead 12]

I've been trying to learn how to map textures and I'm not quite ready to do it on the airplane itself, so I decided to do it on the engine. This is just a rough draft texture, which will be refined later, so don't pick it apart too much. It's whole purpose is to help me get the polys mapped, and also make the engine itself look better. I textured 1 cylinder and then cloned and rotated it 8 times, and while I expected this to work, I was still somewhat surprised that it actually did .

 

For them as don't know, mapping textures appears to be quite archane when you read a tutorial on it, but once you struggle with it for a while, it makes sense, mostly. Anyway, I think I got the cylinder textures in the right place.

 

The only changes to polys since last time is that I added spark plugs to the cylinder. Now I'm going to texture the crank case, and once that's done, I'll Boolean the whole thing together (I hope).

[ConradB 0]

Looks real nice there BH! I don't to be critical of other's work on their dreations, as I'm sure the creator sees every little flaw and crucifies themselves enough without adding to fire, or lets just say, I don't want to try to put out a fire with a big bucket of gasoline.

[Bullethead 12]

Looks real nice there BH! I don't to be critical of other's work on their dreations, as I'm sure the creator sees every little flaw and crucifies themselves enough without adding to fire, or lets just say, I don't want to try to put out a fire with a big bucket of gasoline.

 

Aw c'mon, it's not THAT bad, is it?

 

The cooling fins, I'm afraid, are always going to have something of a moire' effect when seen at any angle, which will at least always be the case for 8 out of 9 cylinders. However, I hope to minimize this when I do the real skin.

 

What concerns me the most is the Z-buffer problems you can see in the pic. Notice the top cylinder, how you can see the rocker arm and valve stem through the walls of the cylinder head. Then notice on the 2nd cylinder from the bottom how you can see the rocker arm mounting brackets through the rocker arm.

 

I infer that when showing the surfaces of objects instead of wire frames, Gmax draws polys in the order they were created. In this case, the order of creation was valve stem, rocker arm, then mounting brackets. All polys have been Booleaned into 1 object, but still they retain the order in which they were drawn, probably something to do with the numbers Gmax assigns to the polys. I hope this is just the way Gmax displays things and not how the game does it.

[hairyspin 1]

We shall of course expect several oil leaks and staining! If we have to wait for polys to be drawn in the sim, 'tis time to buy a new rig methinks!

Edited February 19, 2010 by hairyspin

[Bullethead 12]

We shall of course expect several oil leaks and staining!

 

Yeah, when I do the real texture, it's going to be liberally coated with the dark brown varnish of burnt castor oil, at least in the areas around the cylinder heads. The rest of it will be covered more or less thickly with slightly yellowish castor oil "jelly" (unburnt oil that's lost water content and turned to sticky goo). Leaves, grass blades, bugs, and blobs of mud will be stuck in this gunk.

 

NOTE: I have no idea if veteran rotaries looked like that back in the day, but I imagine they must have given my experience with RC model engines.

 

If we have to wait for polys to be drawn in the sim, 'tis time to buy a new rig methinks!

 

I don't wait on them to be drawn. I have a killer rig. When I change views, it's POOF! there it is.

 

HOWEVER, regardless of rig speed, polys are always drawn in a specific order, and the last poly drawn is always on top of those drawn before in the same part of the screen. In games, there's a thing called the Z-buffer, which dynamically changes the draw order of polys based on your LOS to them, so that the most distant poly is drawn 1st and the closest poly is drawn last. Gmax, OTOH, seems to lack a true Z-buffer. It seems to draw polys by entire object in the order the objects were created, so that newer objects are visible "through" (really on top of) older objects. Then within objects, the individual polys are drawn in numerical order of creation.

 

At least I HOPE that's what it's doing. That theory matches observations. However, I haven't yet seen this thing in the game so I don't know if it'll do better there.

[ConradB 0]

Aw c'mon, it's not THAT bad, is it?

 

The cooling fins, I'm afraid, are always going to have something of a moire' effect when seen at any angle, which will at least always be the case for 8 out of 9 cylinders. However, I hope to minimize this when I do the real skin.

 

What concerns me the most is the Z-buffer problems you can see in the pic. Notice the top cylinder, how you can see the rocker arm and valve stem through the walls of the cylinder head. Then notice on the 2nd cylinder from the bottom how you can see the rocker arm mounting brackets through the rocker arm.

 

I infer that when showing the surfaces of objects instead of wire frames, Gmax draws polys in the order they were created. In this case, the order of creation was valve stem, rocker arm, then mounting brackets. All polys have been Booleaned into 1 object, but still they retain the order in which they were drawn, probably something to do with the numbers Gmax assigns to the polys. I hope this is just the way Gmax displays things and not how the game does it.

 

 

No it isn't bad at all man! Considering the boundaries that we have to consider with the CFS3 base software, I think its great. Just have to figure out how to get them rockers and valves animated. Do you have any ideas on how one could simulate valve springs? It is perplexing for me.

 

With the inline 6, I don't have to worry about any cooling fins on the cylinders. It's pretty straight forward on it. Block, cylinders, intake manifolds, exhaust manifolds, and collector pipes.

Edited February 20, 2010 by ConradB

[hairyspin 1]

Simulate the valves and rockers? While the engine is spinning? I doubt anyone could see that! In any event, this is not FSX and rotating engine is all CFS3 allows us.....

 

 

[Bullethead 12]

Just have to figure out how to get them rockers and valves animated. Do you have any ideas on how one could simulate valve springs?

 

Do you have the official Gmax tutorials available at TurboSquid? The 3rd chapter ("Adding the Ramp") of the 2nd tutotrial ("Making a Level") describes how to make a helical object. In this tuturial, they started with a box primitive but I expect the same technique would work with a cylinder. Based on this tutorial, I'd expect the process for making a valve spring would be kinda like real life, where you bend a piece of wire into the spring shape. Here's my suggestion on how to do it:

 

1. Create a cylinder with MANY height segments in the top view, so its long axis is parallel with the valve stem. The cylinder's radius should be the same as the wire the spring is made from.

 

2. In the top view, the finished spring will appear as a circle some distance out from the valve stem. Move the cylinder so that it's X coordinate is 0 and its standing on the circle where the finished spring will be.

 

3. Texture the cylinder as you want the spring to look, before you do anything else. I imagine it would be a total bitch to texture it after you bend it into a spring.

 

4. Apply a Twist modifier to the cylinder.

 

5. In the Parameters rollout for the Twist modifier, set the angle to the desired number of spring coils * 360. Now you've got a barber pole that's still cylindrical.

 

6. Select the center object of the Twist modifier and move it to the center of the valve stem. This turns the barber pole into a helix.

 

Or at least that's my best guess.

[hairyspin 1]

Or you can draw a helix and a circle - both from the Shapes tab - and Loft a spring. The best tut on Lofts I know of is at the end of Gerard van der Harst's low-poly tut at SOH's Aircraft Design and Animation forum.

 

 

 

A little fiddly to begin with, but the results can be quite splendid. Worth spending some effort on.

 

[ConradB 0]

Ok, cool guys! I was wondering how to get that goin'. I will keep the mostly hidden parts of the engine very low poly, since they aren't seen anyways, and save them for the cool little details. Even if they can't be animated, just having them would be really neat.

 

From all the tutleage you'se guys have given, I've become adept at figuring out where to save on polys, so if you need them elsewhere, they are there to be had.

[ConradB 0]

Simulate the valves and rockers? While the engine is spinning? I doubt anyone could see that! In any event, this is not FSX and rotating engine is all CFS3 allows us.....

 

 

 

Sorry Hairyspin, just bein' my fiesty smart@$$ self. But hey, if I can figure out a way to get another ounce out of something, I will do it. Just to keep the gray matter exercised.

[Bullethead 12]

OK, finally got the engine finished. Booleaning all the cylinders on was a pain, but I learned a lot about how to do it. One thing I found very helpful was hiding various vertices and polys so I'd be able to find the ones I wanted despite the strange angles.

 

I also got the texture to a point where I'm pretty happy with it. I've made a bunch of skins so that wasn't too hard; the non-intuititive part was learning how to map it, but I think I've got that down now, too. As you can see on the texture, the cylinders and spark plugs have the same thing front and back, while most of the rest are wrap-arounds. The real fly in the ointment was making the 3 rings of nuts around the front of the eninge, so I laid out the texture based on them.

 

The whole damn engine has over 5000 polys. However, this is is the LOD100, stationary version. As such, it will only ever be seen in a close-up external view with the motor off, like you were doing a walkaround. The LOD90 version will be MUCH more austere, and of course when the motor's running there'll be a very, very simple version (I'm thinking a single short, fat cylinder with a blurred texture on it). So I figure I can live with all the polys of this version of the motor. If it turns out I can't once I get to the point of putting the plane in the game, I guess I'll have to scrap it and start over. But for now I'm pretty proud of it

 

[hairyspin 1]

FSX here we come! Looks very good, although quite polygonous, but you can always simplify later. Much more importantly, you're getting the hang of mapping your own model.

Funny how what we think is a small job takes ages, but modelling is like that. The first 90% of the job takes 90% of the time - the last 10% takes the other 90%. (programmer's estimating rule)

[Bullethead 12]

FSX here we come! Looks very good, although quite polygonous, but you can always simplify later.

 

Do you think I'll have to simply this LOD100 stationary version? I was thinking that because you'd never see it from the cockpit nor even on your wingmen, it was OK. I just made it for close-up glamor external screenshots.

 

Funny how what we think is a small job takes ages, but modelling is like that. The first 90% of the job takes 90% of the time - the last 10% takes the other 90%. (programmer's estimating rule)

 

Yup, and my bosses can never understand that :).

[hairyspin 1]

We all have bits of an aircraft we think should be modelled in detail - for some it's undercarriage, for others it's engines and props or detailed cockpits, some area we think adds to the immersion factor since the sim won't reproduce every last rivet in photo-realistic detail without slowing to a shuddering, stuttering halt.

 

The Gnome will, as you say, only show the details while stationary and just after the erk shouts contact! so the fps hit will be negligible, unless some Hun puts a bullet through the magnetos mid-furball reducing all to a deathly hush. Then you may have the pleasure of gliding to the ground in slideshow mode!

 

Best thing is to try it out in the sim...

[Bullethead 12]

The Gnome will, as you say, only show the details while stationary and just after the erk shouts contact! so the fps hit will be negligible, unless some Hun puts a bullet through the magnetos mid-furball reducing all to a deathly hush. Then you may have the pleasure of gliding to the ground in slideshow mode!

 

Best thing is to try it out in the sim...

 

Hehehe, I can be like Captain Goldwater in the Super LBJ comic book, flying a plane with just a right wing ("Who needs a left wing?!?!?!?) simply by substituting my model for some existing plane on a temporary basis. But won't I have to build the VC for that?

 

And anyway, isn't the game engine smart enough to tell that the engine is in no way visible from the cockpit? I mean, there's all this upper fuselage decking MGs and their ammo belts, not to mention the cowling and firewall in the way. Or is the game really that stupid?