Mecha Construction - Basics

Haftoof

So most mecha can be very detail heavy, pipes, crevaces and lots of pistons.

I'm wondering for lower poly game-engine quality mecha, how do they fill the space. The areas between major panels. I assume that some of the pistons can be modeled but what about the areas inbetween panels. Is it just a single flat surface that they cover with light and texture?

Are there any suggested techniques for these "Gaps"



I'm still working on the side-panel so if it differs from the concept that's because the different perspectives differ slightly. Anyways the areas in red are what I'm getting at.

MethodJ

Since those areas are largely concealed by the outer plates, you don't want to spend a lot of time and attention there (the viewer won't see it).

My first priority would be to fill in the gaps so the viewer can't see straight through the character - I'd fill it with simple shapes, e.g. a single low-res cylinder for the elbows. You could then project the pistons/wires/pipes etc from the interior onto that cylinder and call it a day.

Then again it depends on poly budget, with modern game hardware you might be better off just building all the different pieces parts in there. In that case I would do a lot of duplicated geometry, again, because the viewer won't see much of what is going on in there.

Haftoof

My thought was to build out the shoulder joint very similar to the miniature (using a ball and socket joint and allow for the shoulderpad to cover it view wise.

As for the face my thought was to simply connect the two panels (upper and lower) with a flat panel and run a couple of pistons and a cable back from the head into the "core" of the body.

Thanks for the thoughts, any others would be appreciated.

AimBiZ

Basically just fill the gaps in what ever way you find works the best visually. This is a good opportunity to think about the major forms and what supports the silhouette. If it doesn't add to it then it probably doesn't need to be modeled and can be defined in the maps.
Still depends a lot on what you're going for technically. If you're going to use normal maps you could probably put in most of the detail there and only have the most essential forms defined by the mesh. Same goes of course if you're just going to use a diffuse. The less you define in the mesh the more needs to be done in the maps.

Most importantly though it needs to look good. If putting in that extra geo makes it that much better then do it. Just keep it reasonable. The mesh you've got so far seems to be a bit excessive but I don't know what stage it's in.

Haftoof

So I'm still picking things up, I understand mesh economy a bit (I'm mostly stepping through the entire process).

But! for learning purposes, where do you feel that the mesh has excessive detail?

CheeseOnToast

It's a bit of an open-ended question. It largely depends on how much of the screen the model will fill. For a first person game, I'd generally let anything that's raised less than an inch (roughly) from a major surface be handled by the normal map. A unit for a top-down strategy game Would be a different story altogether.

Can you provide a bigger screenshot of just the model? I'll try a little paintover to show how I'd reduce it.

Haftoof

With and without the mesh... what you are looking for?

Haftoof

Basically I'm going through what I've learned of maya so far. I probably should of set a poly requirement but I want to play with the form and step through the workflow on my own model.


I also would love to learn the process of importing it into a game engine and the steps required for that, but that can come later after I've finished the mesh and such.

CheeseOnToast

Here's a quick paintover. There's more I'd do, but it's a bit tricky to show clearly what I mean. Basically, you have quite a few redundant edges which aren't contibuting much to the model's silhouette. You can let the normal map reperesent a lot of the smaller details that you currently have modelled in. Spend your polys on making some of the bigger shapes a bit smoother, such as the front reinforced edge of the hooded part.



If you haven't seen the free "Vertex" book, grab it from here :

http://www.artbypapercut.com/

Take a look at Tor Frick's mech, how he contructs the high and low poly. You might be surprised by how low you can go.

Haftoof

Ah I see, so instead of detailing it in the mesh you just utilize the texture and normal mapping to apply the depth and detail instead of the mesh itself.

Are there any easy ways to do this in maya? Or would you use the texture in combination with something like bumpmap?


Thanks for the resource on texture, I'll definitely read it over and see what I can take from it.

AimBiZ

General tip, you should have the entire character blocked out to get the forms right before jumping into refining things. In this case it will also help you get a better idea of how dense the mesh should be.

Neox

Haftoof wrote: »

Ah I see, so instead of detailing it in the mesh you just utilize the texture and normal mapping to apply the depth and detail instead of the mesh itself.

Are there any easy ways to do this in maya? Or would you use the texture in combination with something like bumpmap?


Thanks for the resource on texture, I'll definitely read it over and see what I can take from it.

it depends, is this supposed to be the highpoly basemesh to bake normals from? As you spea of normalmaps, you will need a highpoly to grab these from

Haftoof

After reading some of the vertex article I'm definately missing something in my understanding. I've got the basics in maya, so I'm gonna go out on a limb here and say that I need to understand the process of baking normals, and the workflow of high poly vs low poly. I'll definately take a step back from detailing and block out the rest of the model as my next step though.


As for the normals... Correct me as I stumble through this for my own understanding...

You build a highpoly basemesh for detail, bake normals from it and apply those normals to a lower poly model in combination with a texture to get the detail without including it in the mesh. Are there any good run-through tutorials that teach some basics of that workflow? I'm working in Maya and while I've worked with applying a basic normal map (generated in bumpmap from a texture) I do not have an understanding of baking from an existing high poly mesh.

Nosslak

Here's a great tutorial for you about baking methods:
https://www.youtube.com/watch?v=OONQzKcWeMY&list=PL6MdElM0q0fqsVDes6xatahjsWq7MggEJ&index=37
If I remember correctly (I just stepped through it real quick just now) the video should show you how to make great bakes with Blender (and maybe xNormal), but most of the workflow should be applicable to whatever application your using.

Haftoof wrote: »

You build a highpoly basemesh for detail, bake normals from it and apply those normals to a lower poly model in combination with a texture to get the detail without including it in the mesh. Are there any good run-through tutorials that teach some basics of that workflow? I'm working in Maya and while I've worked with applying a basic normal map (generated in bumpmap from a texture) I do not have an understanding of baking from an existing high poly mesh.

Your summary is pretty much correct, but if we're being nitpicky, the basemesh is usually a model before the detailing has been done. You bake down the details from the highpoly model, not the basemesh. A basemesh is no longer called a basemesh after it's been detailed or sculpted. It might also be worth mentioning that you usually bake down much more than just the normals as well (I usually bake normals, AO, cavity, curvature and sometimes a heightmap too).

I haven't watched the whole video yet, but this tutorial that was just posted here a few hours ago seems pretty good so far:
https://www.youtube.com/watch?v=6PSrQPizlTY&feature=share&list=UUTFQTh-Nf3sQDwtnN_WKbMw
However this one's more about baking flat tileable textures.

Haftoof

Thanks for the links, some real cool info to listen to on the process of baking. I'll have to find a tutorial to play around with it in maya, gonna work on roughing out the mesh then I'll go back and look at details. The information on UV/edges rules was also good, definately guidelines that I didn't know about and something I suspect is like second nature once you run into the issues.

Also cool to see how the different bakes can be brought into building a texture, my photoshop skills can use every trick n tool I can find and that movie was a grab-bag.

I'll post again once I'm done roughing.

Haftoof

Here's the rebuilt low-poly Head. I took out some of the unnecessary structure, rebuilt the areas you suggested and collapsed some that wasn't really necessary.



I'll rebuild the structure on the hull and remove some of the extra detail and rough out the rest of the model for the next post.

Haftoof

For the Purposes of the torso construction (see previous posts for concept). Is it best to break down the objects by how they move?

What is the best method for things like pistons, hide the ends inside other objects or connect them to the other objects physically?

What are some thoughts I need to keep for the animation step involving these piston structures? I suppose it depends on how I build the joints out... Full joint system (built into the pistons can allow for more complex movement, otherwise the pistons are just for show and I build out the joints normally).

All your thoughts help, thanks!

Haftoof

Better perspective shots.

CheeseOnToast

If you want to challenge yourself, it's possible to make fully working pistons. Since you're trying to learn the whole blockout>hipoly>lowpoly workflow, I'd keep it simple for now though.

I'm just going to lazily post a couple of slipgatecentral's videos to illustrate a good workflow. Notice how he tests animation just by moving the pivot points of objects.

http://vimeo.com/5738519

http://vimeo.com/5734031

Haftoof

I see, man that's helpful to understand the process. The amount of detail he can put in and control and a lot of his curve tricks looks like things I can pick up and learn during the high poly detail section. Added to my sheet of things to look into and read about.

Appreciate it cheese.

My thoughts currently are that the joints as they move down the leg will have to be seperate structures build over each other (so they appear to rotate mechanically rather than deform). The leg from the hip to knee will move around the knee joint's movement. The leg from the knee to ankle around the knee joint, and so on and so forth.

I might play with the structure of the pistons in the future but I'll go with that. I can break down the objects based on that form.

Haftoof

Small Update.

Am I hitting the mark as far as blocking things out?

CheeseOnToast

Looks good so far. Proportions seem about right. You might want to deviate from the concept slightly to fill some of the gaps between all the hydraulic pistons on the lower leg. There's a lot of very sharp concave angles in there which may cause you some problems at the retopology/baking stage if you want to turn them into a single object on the low poly. I'd also revert to the original version of the head, since you're planning on making a highpoly out of this.

Haftoof

I guess the question comes down to if I want to animate the pistons. If I don't then it can be one piece. The pistons on the side can be incorporated into the calf piece at that point and streamlined.

Hmmmm problem solving, I'll concept up some alternate "mechanical" builds to the foot and calf. I'll pull the current work off to the side and rebuild a few concepts. I'll go ahead and play with the pistons in the complex foot off to the side (since I've been reading on how to do that). We'll see what I come up with.

Any other thoughts would be appreciated. I'm trying to pick up the concepts on how to build out keeping the other parts of the work flow in mind (how things will animate, how to apply the high detail to the lower poly). Those movies really helped a lot to let me see the process at a very high end.

Haftoof

Few things I noticed:

- Crotch plate can be moved in a bit.
- The Concept has two toes not three.

I looked at some other warjacks and noticed that a lot of the piston work is mainly focused internal to the pieces.

Thought about a few things:

The pistons on the upper thigh make no sense...
- Make the upper thigh piston more solid.
- Make the lower thigh Piston slightly smaller but push the calf forward.

On the Calf
- Remove the outer pistons, they offer no support (since the knee is single directional)
- Shift the pistons toward into the ankle to control the foot.
- Reposition the frontal piston into the knee cap area to provide force into pushing the calf backwards. This will be tied to the knee and propogate into a gap in the calf.

Haftoof

Any suggestions for improving my hard-surface modeling when I move into detailing? Important things to keep in mind?

So far it looks like keeping simplified shapes, checking them in maya's smooth preview then utilizing supporting edges where it looks funky. I was trying to figure out a bit how he maintained his model with the smoothing.

Need to also understand how the smooth/subdivision works when you get to detailing. Guess I'll go searching about and post once I finish the arms.

Haftoof

So, just a quick mock-up of what I've picked up today as far as hard surface modeling, because this will be relevant for the rest of the model, I want to make sure I understand how the topology works... Does this look right?

- Keep to quads...
- Focus on the topology and how my edge-loops can be used to harden the edges, plan those edges out in advance.
- Geometric shapes to start help. (This was a cylinder, 8 sided, 2 height divisions)

I could probably add more geometry to smooth out the curve along the the top and bottom of the piece?

Where do you go from here? Subdivide? Smooth? Build out more detail?

Nosslak

It looks pretty right but you'll probably need a few more segments to make the circular hole in the shape (I'd go for 12 or 16). If avoidable you don't want to subdivide your mesh as that makes it harder to work with so try to predict how much geometry you're going to need before modeling it.

If I were making this I'd make sure to make blockouts for the whole model so I can see that the model looks reasonable quickly, then go in making meshes about as detailed as this and when I was satisfied with the overall look I'd go for the final details.

Haftoof

Nosslak wrote: »

It looks pretty right but you'll probably need a few more segments to make the circular hole in the shape (I'd go for 12 or 16). If avoidable you don't want to subdivide your mesh as that makes it harder to work with so try to predict how much geometry you're going to need before modeling it.

If I were making this I'd make sure to make blockouts for the whole model so I can see that the model looks reasonable quickly, then go in making meshes about as detailed as this and when I was satisfied with the overall look I'd go for the final details.

Just for my understanding of the theory... I check how the smoothed model looks with the viewport subivision view (3 key) and when I want to commit and go for lower changes, I can duplicate, smooth and proceed from there? Or do I duplicate and subdivide the object?

Just want to make sure I have the idea of advancing from a primitive, downward into more detail as needed down.

Nosslak

You can do that but if you do it will be a lot harder to make bigger changes later down the line like changing the bevel sizes or make the middle section thinner as you'll have a lot more geometry that needs fixing. So I usually try to make my models with as little geometry as possible while still achieving the shapes I want by planning my topology around the details that I need. I try to subdivide my whole models as little as possible as every time you the mesh gets 4 times denser and harder to work with.

For this model I knew I'd need a hole so I made enough geometry to accommodate that hole. Here's what my quick attempt looks like:

If you need lots of much smaller details you might need to subdivide it but for this you shouldn't need to if you just plan ahead a little.

Also if you aren't subscribed to it already you should totally go subscribe to this thread as you'll learn a ton there!

Haftoof

In terms of the end-stages. Let's say that piece looks good. I know you can take subdivision preview and render with it, but how does it affect the UV's? Are you building your UV map off the low poly and using the high poly to define depth and help you build out the details that will be lost in your low?

I guess the hardest part for me is conceptualizing the work-flow so I understand how different aspects of the early stages affect the later.


Update:
Picked up some good details from: http://www.polycount.com/forum/showthread.php?t=97381

Really helps spell it out a bit more. Gonna finish blocking out the details, then I'll start detailing the parts. Appreciate the information guys.

Haftoof

Finished roughing out the arm n gun after an hour of goofing. Also quickly fixed the toe. Gonna start working down the arm and detailing it. Need to build hands.

On the hands I was thinking since it looks very jointed, squares for the main joints connected by smaller squares then I can detail them further. I am not gonna build out the hands as an extension since it looks like the fingers are just ball joints fitted into the hand section.

Anything I should know as I detail? I'll fix the calf in detailing. Gonna reposition the pistons based on my concept sketches I drafted up and integrate them that way they don't have all that free space, they will just be embedded into the calf section.

Haftoof

Starting Detailing:

Finished roughing out the fingers. Tested the digits with the manipulators, super easy. I'll just animate the fingers from the same points using a rigid bind.

Haftoof

Anyone have any ideas on producing the holes on the forearm? I tried a wrap deform, with a series of holes but to much deformation caused the holes to warp (around the wrist). I'm thinking I can smooth and try to build or just make them separate pieces... any ideas?

The problem with separate pieces is they won't match the contour of the wrist.


Update: So I carved out a duplicate of the inner wrist area, changed to nurbs, changed back to polygons to redistribute the polys. Picked faces, extruded and this is what I got. What am I missing from slipgate's video that left them looking like cups?

Reverse normals? Doesn't look like it carves into the surface like his...

Nosslak

You need to invert the normals and also move the pieces outwards (would have been easiest to just scale the planes along the normals before doing anything else, but moving them manually should work too). It might also be a good idea to to extrude and scale up the open edges of the holes so they'll get a small bevel and look better.

Haftoof

I extruded the faces outward, similar to how slipgate did it then deleted the caps.

I guess my question is the normals should be inverted so I'm looking at the back of the faces when I look at the cups? I don't see how it carves into the piece.


Ahhh I see... He keeps the base of the cup literally right on top of the surface... His cups are extremely small, the inverted normals fix the issue of seeing the sides of the cups.

Update:

There we go... so I assume when this bakes out, I'll have cups and I can use shading and color to help with that illusion.

Prism

Looking good, i have seen this concept a few times and i really like it. Did you check out the weekly hard surface challenge ?. Might get a few good techniques from it.