Multiple objects on one UV map?

[ozzman1997]

I just wondered, to map more than one object on a single texture sheet, do they have to be grouped? Or can I just select the objects I want to map, give them all the same material, then lay out their UV's? I want to do this the right way so I can save myself a headache for some other time (like algebra.)

 

[Mathias]

Actually, you should map more than one object on your texture sheets so you're on the right track with giving them the same material and laying out the UV coords.
No need to group parts.

 

[ozzman1997]

So I can just select all the objects I want to map, add an Unwrap UVW modifier, then lay them out and apply the material and start painting? That's kind of how I did it last time but I just didn't know if that was the right way or not.

 

[n4gix]

No. You can map as many objects as you wish to the same bitmap, you must map each object separately...

...unless you Attach them to create a single object, UVW Map the polys, then later Detach the mapped object back to individual objects.

 

[ozzman1997]

So, say if I had the wings, fuselage, and tail assembly I would have to attach them all together, map it, then detach them again? I mean, it worked when I just selected the ones I wanted but I never tested it in the sim, and that's the true test...

What about all the stuff that is animated, like the control surfaces and the landing gear parts? If I attached them all, that would mess up their pivot points and I'd have to re-do them all.

 

[n4gix]

If I plan to UVW Map switches, knobs, needles, etc. to the same bitmap, then I do so before I "Detach" them as separate objects, set the pivot points, and animate them.

Otherwise, I UVW Map all of the static mesh I intend to consolidate to a single bitmap, then use a layered PSD file containing the mesh layout as my background image while I UVW Map and Edit the smaller, animated objects.

This gives me the opportunity to "fill in" all of the unused pixel space of the bitmap without danger of overlapping any of the static mesh object's space.

 

[hairyspin]

This is a map from my Tempest project, produced in Gmax/LithUnwrap and assembled in Paintshop Pro. There are a lot of different parts mapped to this one texture sheet and they were each mapped as individual objects. There's no reason why you can't do the same with Max, if that's what you're trying to do.

 

[ozzman1997]

So you pretty much have to guess where you already put the other parts, so they don't overlap? It looks like your fuselage on the Tempest has a lot of different objects stuck together, did you just scale them down and make them fit together that way?

 

[hairyspin]

No. All objects on that sheet that 'fit together' are mapped with the same map size (41'x41' iirc).

All the wing parts for example have their UVW Mapping gizmo aligned to a fixed position, a dummy object on the model's centerline, and are all planar mapped. There's one dummy for the top view, another for the bottom, so the topsides all align to each other, as do the underneaths. I didn't use UVW Unwrap at all for these.

When it comes to mapping small bits, I do use Unwrap to place them around the sheet, but I tend to decide on a suitable mapping size and stick with it (or use a few set sizes)

Map each part and Unwrap, then render to texture in Max at a suitable resolution - 1024x1024, 2048x2048 etc. Use the resulting bitmaps as layers in a master template in a layer-aware bitmap editor (Gimp, Photoshop, Paintshop Pro, Paint.NET etc.) Use the master as your texture if Max can, or save a copy in .jpg or such as the material for the mapped objects and update in Max with each added layer.

If you can already handle Gmax and LithUnwrap then you'll soon get the hang of it.

 

[ozzman1997]

Yeah the thing is, I never used Lithunwrap correctly with Gmax and I learned to map the wrong way with 3ds (just applying the UVW unwrap to a huge selection and laying them out). So really, I've never textured correctly.

Now...I think I'm understanding this. What I need to do then is make a dummy object to center the whole UV map on, then hypothetically everything mapped planar from the top aligns with the others, since the map is centered in one constant place, then I can go to left/right, front/back etc...Am I correct? To me it seems right, but then again I could be mistaken. Thanks for your patience, Hairyspin. You guys on this forum have been my only way of learning anything!

 

[hairyspin]

This is one of the places I learned!

Nearly right, if you want to make a texture map like mine. All the main wing polys are mapped and the mapping gizmo aligned to one of two dummies. The elevators and horizontal stabilisers are mapped and aligned to other dummies.

The fuselage, on the other hand was done with a cylindrical mapping and was extensively edited in the Unwrap editor to avoid texture stretching - my painter is very picky - and other things like the flap recesses are Unwrap edited for placement on the texture map.

Regardless of editing or mapping method, everything on that texture map is mapped to a 41'x41' mapping size first, whereas in the VC for this model there are certainly three different mapping sizes used, depending on how much of the object is in view.

You could do worse than work through the mapping section of Milton's C162 tut - it's section 22.

 

[lionheart]

I could never figure out Lithunwrap. The people that use it stand behind it strongly. It does produce nice results.

Tom, in all my years of doing this, I had never heard of mapping sections at an exact scale. Wild... Good to know.



What I do is just shuffle things around on a texture sheet to get them to fit perfect, then start applying the mappings to all the parts, but I do them usually one at a time if I can, fitting a new section here and there in the texture sheet, then when I am out of space, make a new one and start filling that up.


Ozz, think of each texture sheet as a bucket of paint, or 'material'. Each part will be hit with a particular 'bucket of paint' or material. Tons of parts will probably use the same bucket/material. You do not have to weld/connect parts with the same material. They are all using the same materials is all.

On a side note, Microsoft tried mapping planes into single texture sheets, such as with the flying Trike aircraft (ultralight). But in doing so, found a flaw, where the compiler will crash if the number of Polygons sharing the same 'material' is exceeded over 65,000 Polys. In such a case, a duplicate Material is created but with a super slight change in 'something' on its settings, then half of those parts on the first material are then assigned the duplicate material.

Tip: I found a quick way of mapping. I clone a part, drag it away from the parts, screen shot it so nothing but 'it' is in the screenshot, paste the screenshot in the texture sheet, fit it into scale in the layers, save, go back into Gmax/Max, refresh teh texture sheet, delete the cloned part, go back to the original part, apply the Material, then map it. This is awesome for 'angles' as you save the angle you are mapping at, screenshot it, and bounch the texture right back onto the part via its UVW. Very fast.

If you do a wing, you do this very thing, 'then' to do the bottom, you go to Polygons mode, click on 'ignore backfacing Polygons, select only the bottom Polygons, double check you have 'only' the bottom Polys selected, then apply 'another' UVW Unwrap, and select the little mapping grid in the UVW Unwrap edit window and drag them over to the 'bottom of the wing side' on the 'texture sheet' and Voila, you have remapped the bottom of the wing by simply dragging over their coordinates grid to the other area on the texture sheet.

To do this, you have to collapse the stack each time on the part to re-change Polygons mappings.



Bill

 

[Heretic]

We've got mapping tutorials/workflow samples in the wiki:

GMax + Photoshop (by Vitus): http://www.fsdeveloper.com/wiki/index.php?title=Texturing_complex_models_in_GMAX
3ds Max + GIMP (by yours truly): http://www.fsdeveloper.com/wiki/index.php?title=Mapping_and_texturing_models_in_3DS_Max

Might still need a version for GMax + GIMP.

 

[n4gix]

To do this, you have to collapse the stack each time on the part to re-change Polygons mappings.

There's no burning need to collapse the stack, simply add a Mesh Select or Poly Select modifier to the stack, and keep on trucking...

From the "Did You Know" department:

Suppose you have a bunch of identical switches to UVW Map for texturing...

Did you know that you only need to UVW Map/UVW Edit one of them? Before you collapse the stack for the first one, hover the mouse over the last UVW Edit modifier, right-click and choose "Copy."

Now, select your next switch and "Paste" the copied UVW Edit modifier on it's stack.

Rinse and Repeat for every identical switch.

That sure saves a BUNCH of time!

Similar to the above, suppose you have a bazillion buttons (such as an FMS) you need to map. By using the above technique, all you need to do is click on Edit to open the UVW Editor, lasso all the vertices, then slide them onto the next buttons image.

 

[hairyspin]

I could never figure out Lithunwrap.

All LithUnwrap does for Gmax modeling is give us an accurate, repeatable way of making a bitmap of the mapping. Accurate. Repeatable.

If you like, it lets Gmax users render a mapping to a bitmap texture like Max does. I use it because that's what I learned from Uncle Milton's C162 tut, but I've yet to read of another method for Gmax which will better it. There are certainly other ways, but none I know of yet which is an improvement.

The Tempest texture sheet is laid out as above to make it easier for my painter to apply camo schemes to this warbird. For an example of his work, see the Showroom thread

 

[ozzman1997]

That's an interesting technique, Lionheart, I've heard of people doing a screen-shot of objects but I didn't know why. Now I do! Here's my game plan for texturing this bird: (feel free to correct me if I'm wrong on a part. )

-Step 1: Select all the parts I KNOW are going to be on this particular texture sheet, Hide Unselected, go to the Color panel and change the color to a highly visible one.

-Step 2: Go to the wireframe orthographic view that is on the right view for optimal mapping, "SNAP", screenshot, then bring it into GIMP and reposition/scale it (keeping the aspect ratio) to the desirable size on my map. I would repeat for the other parts until I had a good, full map of all the parts semi-equally spaced.

-Step 3: I will save the texture and create a new material in MAX using it as the background texture in the material editor, then apply an UVW Map/ Unwrap UVW modifier to each part selected and use the background as a template to fit all the parts into. Then I'd render a UVW template and use that as the diffuse texture in the material editor, and apply that to the parts I map.

Then again, I could have missed something really important in the process...

 

[Zeiten]

Since you are using MAX you have a feature called "render uwv template".
You will find it in the tools menu in the EDIT UVW window.

Then when you have saved the new bitmap it will tell you where the "part" is on the texture sheet.

One thing you can do afterward is in the EDIT UVW window is to insert your new template as a background.

Where is stands "Checkerpattern" you select "pick texture"

Select the template you just made and voila you see where you have free space

 

[lionheart]

Man, I wish I had 3DS Max. What an expensive program. I must find a way to get rich in this field.

That's an interesting technique, Lionheart, I've heard of people doing a screen-shot of objects but I didn't know why. Now I do! Here's my game plan for texturing this bird: (feel free to correct me if I'm wrong on a part. )

-Step 1: Select all the parts I KNOW are going to be on this particular texture sheet, Hide Unselected, go to the Color panel and change the color to a highly visible one.

-Step 2: Go to the wireframe orthographic view that is on the right view for optimal mapping, "SNAP", screenshot, then bring it into GIMP and reposition/scale it (keeping the aspect ratio) to the desirable size on my map. I would repeat for the other parts until I had a good, full map of all the parts semi-equally spaced.

-Step 3: I will save the texture and create a new material in MAX using it as the background texture in the material editor, then apply an UVW Map/ Unwrap UVW modifier to each part selected and use the background as a template to fit all the parts into. Then I'd render a UVW template and use that as the diffuse texture in the material editor, and apply that to the parts I map.

Then again, I could have missed something really important in the process...

Ozz, what I do is 'stack' the screenshots up. I do one part at a time (one), shoot it, then alt-tab into my graphics program, texture sheet waiting, paste in the new screenshot as a layer, then I select around the edges of it, reverse the edges and delete the outer edges of the screenshot (screen edges of Max/Gmax, windows, etc). I then use Magic Wand and select the gray area around the part and delete that. now I have 'just' the one part in that layer there. I can now move it and scale it into a zone in the texture sheet.

I do this in 'wireframe mode' as like the plane above in the post by Tom so when you map the UVW to the texture, you can use the lines of the screenshot to line up the part mesh with.

I will usually make all of the layers of 'mesh' (wire frame screenshots) into a single layer, label it 'Templates' and then above it, I make my actual art graphics layers (bottom coat of paint, stripes, shading, mud, rivets, etc) in the upper layers in the graphics sheet.


Thats how I do it. Works fine for me. Dont think of doing many parts at once, mapping them. Think of doing one at a time.

You 'can' combine several parts into one if you want, like an engine block, brake caliper assembly, etc, which would all use the same Material (important) and then map all of the parts separely using my technique above. I do that alot now also (multiple parts assemblies welded together) which enables me to move them around more easily and I can move them out into other plane projects later, recyling them.



Bill Leaming, great advice there.

 

[Heretic]

...

Instead of screencapping a viewport to get the mesh into GIMP, try this:

(I suppose you've already created a material referring to a basic texture file (empty 2048² px or 1024² px file with just a background color) in the "diffuse map" slot.)

- Upon being finished mapping your first part in the UVW Editor, disable the texture view (blue checkered box) in the editor. You should now see the thick outline of the texture sheet.

- Zoom in and move the view until the outline barely touches the toolbars (leave a few pixels of space to make sure) at the top and bottom of the Editor's window.

- Select the vertices of the mapped part and press the "freeze" icon (thermometer; bottom toolbar). This makes the vertices black instead of red and, more importantly, smaller.

- Press "PrntScr".

- In GIMP, select "Create from clipboard". You should see a screenshot of the whole desktop.

- Select the grey area within the thick bitmap outline in the UVW Editor part of the screenshot with the magic wand tool.

- Then do a "Crop to selection" (in the "Image" menu in the top menu bar).

- You should end up with a square, or nearly square, image of your part's projected mesh on a grey background.

- Deselect everything with CTRL+D.

- "Image" -> "Resize" and resize the whole image to your main texture's resolution (1024*1024px, 2048*2048px or else). If you didn't end up with a square image after the "crop to selection" part, deselect the "keep aspect ratio" setting and adjust accordingly.

- After having resized the image, copy it with CTRL+C.

- Paste it into your main texture file and make it a new layer. If this is the first part you're mapping on a texture sheet, name the layer "Mesh" or something similar.

- Select any grey area surrounding your part with the magic wand and delete it, so that the background color of the main bitmap can be seen.

- Save your main texture file and export it for use in GMax. You can discard the temporary image made from the screenshot as you won't need it anymore.

- In Gmax, go to the material editor, select your texture in the "diffuse slot and press the "reload" button. You should now see your mapped part with its temporary wireframe texture in the viewport.

- Map the next part. In the UVW Editor, you can now see where your other parts are located on the texture sheet (and avoid "overmapping" them accordingly) before you disable the texture view and repeat the above procedure.

- On your main texture, you can unify the mesh layers into a single layer. Make sure you remove the excess grey color around the parts though.


So much for my workflow. It is not as accurate as the "render to texture" functionality of 3ds Max, but it does the trick.

 

[ozzman1997]

Yeah, I think the Render to Texture and UV editing tools in 3ds max are some of the only advantages of it over Gmax. That's why I always hated texturing in Gmax, the screen capture on my low-res monitor was never accurate enough. Now I have a 24 inch LCD flat panel. Anyway, Lionheart, I tried your strategy and it worked perfectly. I'm about ready to paint the landing gear of my challenger jet and this will come in handy. (A pic of the gear is in the attachment, man I love those things!)

And as for 3ds Max, the only reason I got my hands on it is because my school has a contract with Autodesk and us students get their software for free.