How should I go about UV mapping this object?

[bananashavings]

Hey, I recently made a propeller model, and it went pretty well. After I finished the modelling, I tried to go in to texturing, but since It was a very complex model, Im not sure how to do it. I want to apply some basic textures to it, maybe a nuclear logo on the tip of the spinning piece, and also colors on the tips of the propellers. Here's the .dae if anyone wants to check it out. I know Im asking a lot, but I would sincerely appreciate any help I can get. Thanks!

[JohnnyPanzer]

I'm going to bed right now, but I'll Download it and have a look in the morning.

A screenshot would be a good idea if you want people to provide you with general tips.

[martinezfg11]

508,544 polygons triangulated, you might want to bring that down a a bit... It's a pretty simple part geometrically, you just have so many poly's it's not feasible for a game engine.

You can achieve that same model with about a thousand tri's. Don't use Subdivision surfaces either unless you are going to do some kind of high poly to low poly baking.

 

Edit: Here's a link

 

Edited April 15, 2016 by martinezfg11
Link Added

[bananashavings]

13 hours ago, martinezfg11 said:

508,544 polygons triangulated, you might want to bring that down a a bit... It's a pretty simple part geometrically, you just have so many poly's it's not feasible for a game engine.

You can achieve that same model with about a thousand tri's. Don't use Subdivision surfaces either unless you are going to do some kind of high poly to low poly baking.

 

Edit: Here's a link

 

I got it down to about 7,000, but I still cant texture it properly. The UV is just so much more complicated than anything Ive seen, that I don't know how to approach it. I could easily get a solid color on each piece, but even trying to get a separate color on the tips of the wings doesn't work as expected. Do you have any tips or ideas on how to approach this? Thanks!

[JohnnyPanzer]

13 minutes ago, bananashavings said:

I got it down to about 7,000, but I still cant texture it properly. The UV is just so much more complicated than anything Ive seen, that I don't know how to approach it. I could easily get a solid color on each piece, but even trying to get a separate color on the tips of the wings doesn't work as expected. Do you have any tips or ideas on how to approach this? Thanks!

The way you describe your problem, I get the feeling you're trying to use a solid color material instead of an actual texture map, is that correct?

Just to be clear, the work method boils down to:

1. Use the available UV mapping tools in your 3D software to unwrap all parts of the model and lay them out in the UV space.
2. Export the unwrapped UVs as an image file so you can use them as reference.
3. Use a 2D software (photoshop or similar) to paint a texture, using the UVs as guidance.

That being said, 7k tris still sounds like it could be streamlined. I'll download you file now and have a look, but for reference, this is the rule of thumb I use for parts in KSP:

• Less than 1,000 tris: Good job, you obviously prioritize a high FPS above super detailed meshes.
• 1,000-3,000 tris: Nice. That will still work, and you'll get a lot more detail in your mesh.
• 3,000-10,000 tris: Now you're pushing it. Are you sure you need all those tris? It'll run, but if you have many parts like that you might notice a consideral drop in framerate.
• More than 10,000 tris: Why? What on earth are you trying to build? Very, very, VERY few parts actually need that many tris in KSP. Most likely, your work method is wasteful.

[bananashavings]

7 minutes ago, JohnnyPanzer said:

The way you describe your problem, I get the feeling you're trying to use a solid color material instead of an actual texture map, is that correct?

Just to be clear, the work method boils down to:

1. Use the available UV mapping tools in your 3D software to unwrap all parts of the model and lay them out in the UV space.
2. Export the unwrapped UVs as an image file so you can use them as reference.
3. Use a 2D software (photoshop or similar) to paint a texture, using the UVs as guidance.

That being said, 7k tris still sounds like it could be streamlined. I'll download you file now and have a look, but for reference, this is the rule of thumb I use for parts in KSP:

• Less than 1,000 tris: Good job, you obviously prioritize a high FPS above super detailed meshes.
• 1,000-3,000 tris: Nice. That will still work, and you'll get a lot more detail in your mesh.
• 3,000-10,000 tris: Now you're pushing it. Are you sure you need all those tris? It'll run, but if you have many parts like that you might notice a consideral drop in framerate.
• More than 10,000 tris: Why? What on earth are you trying to build? Very, very, VERY few parts actually need that many tris in KSP. Most likely, your work method is wasteful.

Thanks for that information, and to clarify, I do want to use a texture map, but I cant accurately place textures on a part in the desired area accurately, as the unwrapped UV mesh is a mess. If you want to see for yourself, heres the model with 7,000 tris.

[akron]

Can you post a screenshot of your model with a wireframe?

[bananashavings]

2 minutes ago, akron said:

Can you post a screenshot of your model with a wireframe?

Here you go, tell me if those are good enough

[akron]

Yes. Follow up question: What size will this be. 1.25m? 2.5m?

[heliobyte]

18 minutes ago, bananashavings said:

Thanks for that information, and to clarify, I do want to use a texture map, but I cant accurately place textures on a part in the desired area accurately, as the unwrapped UV mesh is a mess. If you want to see for yourself, heres the model with 7,000 tris.

I took a quick look at your model and your UVs are easy to fix. You just need to straighten them out. Alt+Right Click, then press W and select "align x" and "align y". You can also try different types of unwrapping (depending of the shape of the mesh). That little things shouldn't take more than a couple of minutes to sort out. Once you've got your UVs done, then simply export the UVmap as an image and import it into PS or GIMP and start texturing

[bananashavings]

3 minutes ago, heliobyte said:

I took a quick look at your model and your UVs are easy to fix. You just need to straighten them out. Alt+Right Click, then press W and select "align x" and "align y". You can also try different types of unwrapping (depending of the shape of the mesh). That little things shouldn't take more than a couple of minutes to sort out. Once you've got your UVs done, then simply export the UVmap as an image and import it into PS or GIMP and start texturing

Doing the Align X/Y looks like its just jumbling it up? It that what its supposed to do?

[heliobyte]

1 minute ago, bananashavings said:

Doing the Align X/Y looks like its just jumbling it up? It that what its supposed to do?

No, it is not supposed to do that. In the UV Editor, the horizontal edges needs to be aligned to Y, and the vertical edges needs to be aligned to X. Remember to use ctrl+E to mark seams before your unwrap. Especially when unwrapping cylindrical/semi cylindical meshes.

[JohnnyPanzer]

Yeah, looking at your UVs I concur with @heliobyte, it should be an easy fix. I suggest you look up some tutorials on how to use the UV tools in your 3d software of choice. It's hard to give direct advice on exactly how to do it, since you can use more than one way to get the same result.

Still, if I were you I'd take those propellers down a few notches. They have more curvature detail than they need, and you could easily get your model down to less than 1,500 tris without much loss of detail. But then again, 7k tris is not going to bring the game to a halt, so it's up to you. For reference, I threw together a very quick "sketch" of your model to show how it could be done with less tris, but this was before you posted your updated images and it does not include propellers. Still, you can see that it has pretty much the same level of detail when viewed from a distance, and weighing in at less than 500 tris, you'd still have another 500 or 1,000 tris to spend on the blades. I also included some screens of one of my models along with the textures (UVs laid on top) in case that would help you figure out how to properly unwrap things.

 

[bananashavings]

8 minutes ago, heliobyte said:

No, it is not supposed to do that. In the UV Editor, the horizontal edges needs to be aligned to Y, and the vertical edges needs to be aligned to X. Remember to use ctrl+E to mark seams before your unwrap. Especially when unwrapping cylindrical/semi cylindical meshes.

I pretty much fixed the Main Engine's UV, but if you could quickly take a look at the "Spinners" UV and tell me if thats possible to fix that would be great. To me that looks impossible, but then again Im not that experienced. Thanks again!

[akron]

Before you follow the above advice, I suggest you take a look at your polygon density. You can definitely cut that model down to or under 2000 polies without a loss of silhouette. The cylinders behind the cap are not very visible and are taking up far too many polygons. The blades can each be reduced to half that level of detail. The main engine can have a good outline with only 24 edges.

[heliobyte]

Just now, bananashavings said:

I pretty much fixed the Main Engine's UV, but if you could quickly take a look at the "Spinners" UV and tell me if thats possible to fix that would be great. To me that looks impossible, but then again Im not that experienced. Thanks again!

There is not need for me to take a look. You do not need to unwrap the entire mesh of each propeller blade in one go. Simply select the top half of the faces and unwrap those, select the bottom half of the faces and unwrap those. Quick and easy. The same goes for most meshes, unwrap the faces that makes sence, then unwrap the rest.

[JohnnyPanzer]

The reason we keep nagging about the polygon density is partly because unwrapping becomes more and more confusing the more polygons you have. It's so much easier to wrap your head around it all when you don't have to deal with thousands of polygons that serve little to no purpose. Try to ask the following questions whenever you start work on a new part of the mesh:

• How visible is this part going to be?
• How much attention will it draw?
• Will it be moving, and if so, how quickly?
• What's the minimum number of edges/sides needed to produce a good looking silhouette?

Meshes that are hardly ever visible, will be moving too fast for anyone to get a good look at or are downplayed by nearby, more attention grabbing parts, should get the least amount of detail. Save your polygons for the show stoppers. In this case, that would be the main body and the large blades, the small diagonal blades behind the cone will hardly ever be seen, so they would hardly need any detail at all. And even for the main body/blades, a nice looking silhouette could be produced with fewer sides. The number of vertical edges is fine, you need them to be able to follow the curvature properly.

As for UVs, allthough I'm unfamiliar with Blender and the UV tools provided there, there are a few things one should always keep in mind regardless of the software used:

• Can I reuse the same UV space? For example, would each blade need it's own unique texture space, or could their UVs be placed on top of each other.
• What's the best placement for my seams? Seams should be hidden as much as possible, or placed in a manner that makes it easy to paint them seamlessly. On the blades, the edges would be a good place for seams.
• Can something be mirrored? For example, if you know that both sides of the main body will look roughly the same, then place seams at the top and bottom, flip one side and place it on top of the other side.
• What's the best projection method for a particular piece? A cylinder might be best projected using a cylindrical projection. A plate would be better served by a planar projection.
• Would this piece look better relaxed? Most software have some sort of relax function. On meshes with lots of curves, this can be used to great effect.

Another tip is to use a checkered material when unwrapping. That way you can easily see if something is scewed, and it will also let you eyeball sclaing issues quickly. If the squares are elongated, you instantly know that the UVs are stretched.

[bananashavings]

46 minutes ago, heliobyte said:

There is not need for me to take a look. You do not need to unwrap the entire mesh of each propeller blade in one go. Simply select the top half of the faces and unwrap those, select the bottom half of the faces and unwrap those. Quick and easy. The same goes for most meshes, unwrap the faces that makes sence, then unwrap the rest.

If you look at this picture, you can see that I have a circular area selected but its more of a rounded diamond in the UV editor. Is there a way to fix that, because It makes it very hard to try to apply a texture to that area. Thanks!

23 minutes ago, JohnnyPanzer said:

The reason we keep nagging about the polygon density is partly because unwrapping becomes more and more confusing the more polygons you have. It's so much easier to wrap your head around it all when you don't have to deal with thousands of polygons that serve little to no purpose. Try to ask the following questions whenever you start work on a new part of the mesh:

• How visible is this part going to be?
• How much attention will it draw?
• Will it be moving, and if so, how quickly?
• What's the minimum number of edges/sides needed to produce a good looking silhouette?

Meshes that are hardly ever visible, will be moving too fast for anyone to get a good look at or are downplayed by nearby, more attention grabbing parts, should get the least amount of detail. Save your polygons for the show stoppers. In this case, that would be the main body and the large blades, the small diagonal blades behind the cone will hardly ever be seen, so they would hardly need any detail at all. And even for the main body/blades, a nice looking silhouette could be produced with fewer sides. The number of vertical edges is fine, you need them to be able to follow the curvature properly.

As for UVs, allthough I'm unfamiliar with Blender and the UV tools provided there, there are a few things one should always keep in mind regardless of the software used:

• Can I reuse the same UV space? For example, would each blade need it's own unique texture space, or could their UVs be placed on top of each other.
• What's the best placement for my seams? Seams should be hidden as much as possible, or placed in a manner that makes it easy to paint them seamlessly. On the blades, the edges would be a good place for seams.
• Can something be mirrored? For example, if you know that both sides of the main body will look roughly the same, then place seams at the top and bottom, flip one side and place it on top of the other side.
• What's the best projection method for a particular piece? A cylinder might be best projected using a cylindrical projection. A plate would be better served by a planar projection.
• Would this piece look better relaxed? Most software have some sort of relax function. On meshes with lots of curves, this can be used to great effect.

Another tip is to use a checkered material when unwrapping. That way you can easily see if something is scewed, and it will also let you eyeball sclaing issues quickly. If the squares are elongated, you instantly know that the UVs are stretched.

Thanks for the reply, Ill try to keep all of that in mind. Unfortunately UV mapping has made me extremely frustrated, and Ill need to take a break for a bit. Hopefully things can go a bit smoother from there. Thanks again!

Edited April 15, 2016 by bananashavings

[akron]

11 minutes ago, bananashavings said:

Thanks for the reply, Ill try to keep all of that in mind. Unfortunately UV mapping has made me extremely frustrated, and Ill need to take a break for a bit. Hopefully things can go a bit smoother from there. Thanks again!

Sure! but don't give up. UV wrapping is something that you will get better at with time and experience. I've been doing this for a few years and I am still a newbie at it.

[JohnnyPanzer]

15 minutes ago, bananashavings said:

Thanks for the reply, Ill try to keep all of that in mind. Unfortunately UV mapping has made me extremely frustrated, and Ill need to take a break for a bit. Hopefully things can go a bit smoother from there. Thanks again!

Trust me, it's not the last time UV maps will leave you frustrated. Most people consider UV mapping to be the boring chore of 3D modelling.  Taking a break is sometimes exactly what you need.

When you get back at the horse, have a look at these various tutorials on how to use the UV tools in blender. It still sounds like you're mostly stuck in "how the hell do I do this"-mode, which suggests that you would benefit greatly by learning the basics of the UV tools. I know that when I started modelling, I spent waaaay longer than I should have struggling with UV maps. Jobs that should take less than an hour would take me days, simply because I never bothered to learn what the various buttons and tools did. Once I read through some tutorials I was amazed at how quickly things could be done. Some things that I had been doing manually, moving each point by hand, one by one, could be done by the press of a button.

https://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/UV_Map_Basics

http://www.chocofur.com/5-uv-mapping.html

http://www.katsbits.com/tutorials/blender/learning-unwrapping-uvw-maps.php

http://sophiehoulden.com/tutorials/blender/unwrapTut.html

Edited April 15, 2016 by JohnnyPanzer

[bananashavings]

20 minutes ago, JohnnyPanzer said:

Trust me, it's not the last time UV maps will leave you frustrated. Most people consider UV mapping to be the boring chore of 3D modelling.  Taking a break is sometimes exactly what you need.

When you get back at the horse, have a look at these various tutorials on how to use the UV tools in blender. It still sounds like you're mostly stuck in "how the hell do I do this"-mode, which suggests that you would benefit greatly by learning the basics of the UV tools. I know that when I started modelling, I spent waaaay longer than I should have struggling with UV maps. Jobs that should take less than an hour would take me days, simply because I never bothered to learn what the various buttons and tools did. Once I read through some tutorials I was amazed at how quickly things could be done. Some things that I had been doing manually, moving each point by hand, one by one, could be done by the press of a button.

https://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/UV_Map_Basics

http://www.chocofur.com/5-uv-mapping.html

http://www.katsbits.com/tutorials/blender/learning-unwrapping-uvw-maps.php

http://sophiehoulden.com/tutorials/blender/unwrapTut.html

Thanks for those sources, and after brushing through those, I understand most of the basic concepts. What Im struggling with right now is trying to figure out why unwrapping a circular area shows up as a deformed diamond. Heres a picture showing what I'm trying to explain. Is this normal, is there anyway to fix it? Thanks!

[JohnnyPanzer]

1 hour ago, bananashavings said:

Thanks for those sources, and after brushing through those, I understand most of the basic concepts. What Im struggling with right now is trying to figure out why unwrapping a circular area shows up as a deformed diamond. Heres a picture showing what I'm trying to explain. Is this normal, is there anyway to fix it? Thanks!

What projection method are you using? Plane projection along the z axis should give you a good result, what's shown in the image is... weird. Almost like a view projection, but with perspective distortion added or something. Could you give us a detailed rundown of exactly how you arrived at those results?

Again, I'm not familiar with blender, but from that image it looks like you are unwrapping vertexes instead of faces, is that the case? It shouldn't matter, but for most cases, you want to unwrap faces and only go into vertex mode when you need to fine tune a projected UV island. If I were more familiar with blender I'd be able to help more, but I've never touched it. I'm used to Maya, 3ds max and Zbrush, but every screenshot I've ever seen from Blender makes it look like it has the messiest, most horrible UI imaginable, so I've stayed away from it. I really should give it a try, because apart from the UI it seems like a pretty powerful free alternative to some of the bigger software suits.

[bananashavings]

1 hour ago, JohnnyPanzer said:

What projection method are you using? Plane projection along the z axis should give you a good result, what's shown in the image is... weird. Almost like a view projection, but with perspective distortion added or something. Could you give us a detailed rundown of exactly how you arrived at those results?

Again, I'm not familiar with blender, but from that image it looks like you are unwrapping vertexes instead of faces, is that the case? It shouldn't matter, but for most cases, you want to unwrap faces and only go into vertex mode when you need to fine tune a projected UV island. If I were more familiar with blender I'd be able to help more, but I've never touched it. I'm used to Maya, 3ds max and Zbrush, but every screenshot I've ever seen from Blender makes it look like it has the messiest, most horrible UI imaginable, so I've stayed away from it. I really should give it a try, because apart from the UI it seems like a pretty powerful free alternative to some of the bigger software suits.

Yeah I use Cinema4D to model, but I decided to try and UV map in blender because everyone else does it. 

[InsaneDruid]

Speaking of mesh density:

I am a true supporter of a fairly high mesh density to improve the looks of a model (like I consider 48 circle elements to be the way better choice over 24 for a 2.5m part), but still I got your model down to 1300 polies just by deleting invisible parts and applying an decimate modifier with 6 iterations of un-subdivide on all the parts and still considered it good quality.

Some basic rules that I follow:

• if something is invisible, don't model it/delete it. The backside of the spinner for example in your original model you linked. Can go. These cylinders inside the spinner on your screenshot? Pure ballast.
• flat surfaces only need vertices on their perimeter. The backside of the model (where it is supposed to be attached to another part) has tons of rings of vertices for nothing. Also the plane that is right behind the spinner and forms the front part of the main engine part.
• wherever possible, join parts to be one single mesh. Why are the flat planes mentioned above separated from the main engine? Why are the blades separated from the spinner (considered they aren't variable-pitch-animated). Having multiple, separate parts increases the amount of draw calls unity will make, which can bottleneck rather soon. I have seen models with hundreds of separate little meshes and everybody wonders why it lags.

 

As for the UV here is what I would do:

• for the blades, use flat projection (project from view) for the front and back of it.
• for the spinner, I'd probably also use a flat projection from the front, with some manual tweaking/stretching of the outer polygon rings. This way it is easy to paint like a spiral on it without hassling.
• for the main engine body, I'd separate the front and back flat faces (the ones mentioned above twice) and use a flat projection on them (especially as these are surfaces that can have a lower texel density as they aren't seen that much), and then use a simple unwrap or a cylinder projection (make a seam on the bottom of the part going from front to back) for the rest of it.

[heliobyte]

7 hours ago, InsaneDruid said:

Having multiple, separate parts increases the amount of draw calls unity will make, which can bottleneck rather soon. I have seen models with hundreds of separate little meshes and everybody wonders why it lags.

Yes, people really need to stop parenting details. If it doesn't need to move and if it isn't animated, it doesn't need to be a separate mesh parented to the main mesh. Parts like engines, solar arrays and so on are fine, but the rest can be joined to the main mesh.

Also, some modders needs to learn how to optimize colliders. Believe it or not, some of them actually duplicate the entire part (often times a high-poly mesh) and uses it as the collider. That is a big no-no in my book.

Finally, optimizing the UV map. I think people would be amazed with how much you cram into one 1024 UVmap if you know how to utilize the space available. I usually try to fit 3-4 parts worth of texture on one UV map. Unless it's a high def replica lifter with a bunch of logos, one can easily have 3-4 parts share 1 UV map.

Edited April 16, 2016 by heliobyte