Better Modeling with Meta/Pep/P.N – Tutorial 1: Introduction

Discussion in 'Tutorials' started by Jaybats, Jan 21, 2008.

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1. JaybatsMember

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hi, JT, sorry i didn't check the thread to see your earlier posts.

to make a hole in a square in MetaLE, the procedure is basically the same as for making the indentation, except that instead of a globe you use a cylinder. remove the middle point at each end of it, invert the faces, and align the ends of the cylinder with the corresponding sides of the cube. delete the sides of the cube that you don't need, and then connect the points of each end of the cylinder to the corresponding 4 points of the side of the cube to which it is aligned. you'll still end up with what sjsquirrel shows in the 2nd image he attached.

your idea of converting a donut could work, using the "align vertices" command to flatten sides. but you may have to spend more time in making sure that they outer sides form a square, and each side may be divided into more faces than you would like (depending on how round the inner hole is).
2. eric_sonMember

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Hi,

How can I determine what bitmap dimension I have to use to prevent uneven stretching when it becomes mapped on to my object?

Thanks!

Eric
3. JaybatsMember

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What kind of "stretching problem" are you having? I've noticed at least 4 types:

...(a) when the proportion of texture on the image map is not the same as the proportions of the model (e.g. the Meta model of the rocket is 5 units long, but the texture map of the rocket is 4 units long)

...(b) the image map resolution is so low that individual pixels stretch out (e.g. the texture map is only 200x 200 pixels, and is spread over a large area that measures 6"x6" when printed)

...(c) the texture is flat mapped at an angle (e.g. the face is at a 40 degree angle to the texture)

...(d) when there's only one Material and texture assigned to several faces, and the alignment in one face on one part of the texture needs to be adjusted without altering the alignment in another part (e.g. you're texturing a car, and want to move the texture for the front bumpers, but it seems you can't do it without losing the alignment on the rear fenders)

Each issue can be addressed differently:

...(a.1) if your texturing using an image of orthographic views, avoid differences in proportions between your image maps and models.
...(a.2) if possible, use the background image when you make the meta model as your texture (e.g. what was done with the Orbital Inspection Pod), or at least the base for making your texture (e.g. you can color and refine the image of the Orbital Inspection Pod)
...(a.3) if you made the model without a background image, take screencaps of the various sides of the model, color/texture those images, then use them for your Materials

...(b) always use as big and as high resolution images as possible for textures, since Pepakura will scale it down a hi-res image to 1024x1024, but not scale up a low-res image

...(c) use multiple textures, trying to keep them as parallel to the face as possible.

...(d) you can "clone" Materials and apply them separately in different positions to the model, without one affecting the other's assigned mapping. if you don't clone them Meta will stretch and move the entire map, in all faces it is applied to, everytime you make an alteration with any one of the faces.
4. sjsquirrelMember

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Would be Better than you think

EDIT: It turns out Jay and I were both replying at the same time - I posted my reply and found Jay had snuck in there ahead of me. I'm leaving my reply instead of deleting it just to show that theres different ways to skin model, and that Jays brain works better than mine.

Jaybats - I'll keep my mouth shut from now on. You are The Master!

JT Fox -
Believe it or not, I have used the very method you describe , and the results are much better than you would expect. Don't forget that your eyes are one of your most valuable tools in modelling. You know when it looks "right". Your brain is the second most valuable tool.

In the sample I posted above I used a "cylinder" with 16 sides. That's "only" 16 points you have to manipulate into position.

You can accomplish the same thing easily with the LE version:
If you insert a Plane primitive, you can set it's corners to very precise positions that result in easy math. Select two points on the same side and use "Selected/Align Vertices" to align them on the appropriate axis, and align the other sides so you get a perfectly square plane. For example, it might be from (-50,-50,0) to (50,50,0) which is a square, 100 by 100 units in the XY plane. The exact center will then be at (0,0,0). Use the wire tools or knife to split the plane vertically, then horizontally. Now align those cuts to be at X=0 and Y=0. A circle 25 units in diameter will have points at (-25,0,0), (25,0,0), (0,25,0) and (0,-25,0). So, you can make a few more cuts and align them at X=25, X=-25, Y=25 and Y=-25. Very quickly you've got the center point, and four points exactly on the edge of your circle.

Working from this point, you can now "cut" lines from a corner point to another point on one of the horizontal or vertical lines, then move them into position. Points can be moved quite precisely with the controls in the edit panel (Panel/Edit Panel), or by entering values in the Move tool.

Once you have a circle drawn in the middle, you delete the faces of the circle, move the plane off the XY plane to say Z=50, mirror it (Select All, then Selected/Mirror), then create faces to connect all the corners. Now you have a cube, 100X100X100, with a hole in two opposing faces. Connect up the points of the holes to make your inner cylinder.

I did the sample below to illustrate. The circle has 8 sides. Each of the 8 "circle" points were aligned by selecting the appropriate points, then using Selected/Align Vertices, and then adjusting locations so it looked about right. Adding another 8 points wouldn't take much longer.

I started the sample, made some mistakes, deleted the whole thing and started over, then did it again. Total time from start to finish was 13 minutes. It's taken me much longer than that to compose this reply. It may be more work, and it may not be the fastest, but as Jay is trying to stress in this tutorial, you can do a GREAT deal with the LE version of Meta, IF you take the time to learn the tools it provides AND practice with them. It's just work, and in the end your work pays off with a paper model that YOU created. I say it's worth it!

Now, get this! You can cut the work in half by creating a half circle, then mirroring it to create the full circle. You can cut it in half again, by creating a quarter circle, mirror that to create a half circle, then mirror the result to create the full circle. Eyes. Brain. Meta. Keep at it everyone. It really is worth it.

SJ

PS - Don't forget that the registered version of meta is about the price of an ink cartridge.

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5. JT FoxMember

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Thanks for the tips guys.

Time to go away and practice some more till I get stuck again.

Cheers JTF
6. eric_sonMember

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Yep, I'm having problem "a". I created a fuselage, and tried applying a texture using the cylinder mapping mode. Everything turned out pretty well until I started painting the insignias on the textures as part of the 'finishing touches', hehehe. That's when I noticed the severe stretching taking place.

I'll try to redo my textures with a.2 and a.3 in mind. Thanks again.:thumb:
7. eric_sonMember

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After playing around with meta's mapping tool, I've come up with this:

1. Create a new texture. On the new texture dialog/properties, assign a filename to the bitmap to use. Make sure that the bitmap has not yet been created.
2. Apply the new texture onto your object.
3. Fix the orientation.
4. Use the "fit to object" or "fit to selection" function.
5. Bring up the properties dialog and write down on a piece of paper (or notepad) the X and Y sizes that resulted from the previous operation.
6. Bring up the paint panel and resize the bitmap to the X and Y sizes that you noted down on the previous step. If you use cylinder mapping, you will need to multiply the width by 2. You may also want to scale up those sizes a bit.
7. Save the bitmap and edit it somewhere else. (I never really did get a hang of using Meta's paint panel.)

I managed to get very little distortions using the above estimation methods.
8. JT FoxMember

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Some pictures of the project I've been working on.

Next job textures.

Cheers JTF
9. eric_sonMember

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Very nice!

I have a question:

Are the wings, rudder, elevator, etc. attached to the main fuselage as one object? Or did you design them to be separate objects?
10. JT FoxMember

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Hi eric_son.

The plane is made from the following objects.
1. Fuselage
2. Canopy
3. Main Wing Pt1
4. Main Wing Pt2
5. Main Wing Pt3
6. Tail Section
When I finished creating the starboard wing parts I mirrored them to get the port wing.

Cheers JTF
11. JT FoxMember

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A few screen shots with the textures on.

When should I add the colour. Is this done now, before the unfold, or, after the unfold?

Cheers JTF
12. JaybatsMember

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nice work on that super etendard!

you can change the colors anytime you wish since you can manipulate it separately in a graphics program. as long as you don't change the proportions of the original image you're using as texture, the UV mapping will stay the same. you can even change the colors after you've unfolded and printed, to create different paint schemes using the same model.

as a matter of preference, when there are details like that on a model, i reserve the coloring/painting for the last, i.e. just before final unfolding in Pepakura. that way it is easier to align the details because there is less clutter, and sometimes the too many colors can make it difficult to see the model's lines clearly.
13. JT FoxMember

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Rather than wait for the installment on paper unfolding I though I'd go ahead and throw the Dassault SuE into Pepakura.

Result: Too many faces (# of faces 1134). It may take a very long time to assemble.

OK I'll wait for the tutorial.

In the meantime, any advice for the model. Should try and reduce the number of faces?

Cheers JTF
14. eric_sonMember

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Nah.... you can safely ignore that warning. I got the same warning on my model and it unfolded in a flash. I think that warning is only for very low end PC's.

Anyway, did Pepakura also discard any vertices or faces in your model?
15. JT FoxMember

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Not that I'm aware of. Although the unfold was all over the place. Some work required to make sense of it.

Cheers JTF
16. eric_sonMember

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The moment you open your model file (MQO?) in Pepakura, you're going to get a status display message. That where you probably saw that message saying that there were too many faces, etc. In that same status message, you may also get something like, "4 faces discarded, 2 vertices discarded".
17. JT FoxMember

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Nothing discarded.

I've had a look at some other models which come as Pepakura files and they seem to use the approach of having the 3D model exploded.

I might take a copy of my model and cut it up a bit so as to have more objects and then unfold them one at a time. I could then edit each section as required till I get a tidy unfold.

I guess then it comes down to trial building and re-editing the sections as required.

I've DL'ed the demo of "Ultimate Unwrap3D Pro". Anyone use this instead of Pepakura?

Cheers JTF
18. NothingLongtime Member

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any idea when the pdfs will be available? its starting to get hard to find specific points in the tutorials. for some reason i cant figure out how to model a wing. can you point me in the right direction?
19. JT FoxMember

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Hi nothing,

I found wings the hardest part on the Dassault SuE

I've only successfully completed one set of wings, so Im no expert, but I'm happy share.

The drawing I had for the for the SuE had two cross sections for the wing profile, therefore the wing is effectively spit into 3 part.

I created 3 objects, innner wing, middle wing, outer wing. Each object is a cube. From the side view I line middle wing cube up with the profile drawing. Using the knife I cut in vertical lines at various positions. Then I moved the points on one side of the cube to match the profile. I then move the points on the other side to match the second profile.

Switching to top view I lined the plan view of the SuE drawing with the cube. I then move the sides lerft, right, up and down to get the width and angle of the wing.

Switching to the front view I now adjust the sides up and down match the slope of the wing.

That completed the middle section.

I then repeated for the inner and outer wing using best guess technolegy for to get the shape of the wing end without profies.

I used the mirror function to create the wing on the other side.

I suggest you use the same number of vertical cuts in each Cube in case you which to merge the objects and join the vertices. I may wish to you cut the fuselage the same way if you wish to join the wing to the plan. If not you can still get the vertices location to match up and make a good looking join.

I didn't do the last bit and you can see my joins, I even have gaps when zoom in.

Hope this helps, (makes sense).

Cheers JTF
20. JaybatsMember

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hi sorry i am out of circulation for the moment, too much work to catch up on...

there are several ways to make wings. i would usually start with a sectioned rectangle, mold it into its aerodynamic cross-section, then start moving and shrinking the wingtips into position. afterwards i use the Knife to cut it into sections for further manipulation between the wingtips and the wing root. this can be done with the wing either as one whole piece or 2 separate pieces (start with one side, then mirror, like JT says).

there's an older Meta tutorial for FMS which illustrates how to make an airplane, the portion about the wing is useful. i got started off on this one:

shinichiro nishiya
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