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3D Modeling Process Thread

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  • #38114
    Anonymous
    Inactive

    Damn

    #38121
    Max
    Participant

    For those who want to follow along, here are the reference images I’ll be working from. Feel free to download them and use them in your own models. If you post them out anyplace else, please link back to this thread and give credit for the source.


    #38122
    Max
    Participant

    So now that we have our reference images, it’s time to talk about polygonal modeling a little bit. This won’t be too exhaustive, but it helps to get some terminology straight. At the most basic level, a Polygon is the plane described by at least three Vertices (plural of vertex, often shortened to “verts”) connected by Edges. It has a front Face and a back face. The line that is perpendicular to the front face is referred to as the normal. The smallest possible polygon is a 3 sided polygon, so you will often see models described as having X number of Tris to discuss the overall resolution or complexity. When modeling, you want to stay in 4 sided polygons, or Quads, to make it easier for the rendering engines to process them. You can’t always avoid triangles, but you can (and should) avoid n-gons (n-sided polygons, more than 4 sides). You want to try and terminate your triangles in areas that are not obvious, like armpits or some other place that won’t be obviously deforming. That may not make much sense now, but will become clear as we get further along in the process. You put Texture Maps onto the model with Materials and Shaders.

    The first thing we’ll do is load our reference images into image planes. This process is going to vary depending on what program you are in, but it amounts to loading your images in as textures on a plane so you can match up your geometry to it.

    I’m going to use the orthographic cameras to rough in the shape (ortho cameras don’t distort the image for perspective, imagine a 2d image vs a 3d image as a rough approximation of the difference). I’ll primarily be in the front and side, but I’ll switch to the perspective camera to make sure that it looks good from all angles. I model according to a process known as Box Modelling. This is pretty much just what it sounds like. I take a primitive cube, and modify it into the shape I want. You do this by adding edge loops and extruding faces off of it until it matches your reference. I’ve seen people start with a poly plane and extrude the edges face by face, but I find that cumbersome. You can save yourself a lot of time by modelling half of the model, then mirroring the geometry to generate the opposing side.

    #38123
    Max
    Participant

    You really want to work from crude to fine in terms of detail in order to keep the process manageable. What I mean by this is that you’ll want to match up all the extreme points first and block in your basic shape, then you add more geometry to refine your model once the form is solid. If you dive right in to high detail first, you’ll get overwhelmed by all the little changes that will cascade out from everything you do.

    Here I’ve gone into the perspective camera to check my form from other angles. I’ll switch my scene to realtime lighting (with no lights in the scene so it shows up totally black) in order to check for jagged edges in my silhouette.

    #38128
    Max
    Participant

    Eventually you end up with something that looks like this for the head:

    A little trick for making the vents and piping details on the helmet is to use the curve tool to draw out the shape of the tube. You then create a primitive cylinder that has the appropriate roundness. Select the face and extrude the object along the curve you drew:

    Because the helmet is a hard surface that isn’t going to deform, you can just leave the cylinder clipping the helmet and combine the objects. You’ll want to go in and delete any faces that are never going to be seen so that they won’t bloat your model with unnecessary polygons.

    #38130
    Max
    Participant

    Here is the finished helmet with the piping and details modeled in.

    #38146
    Max
    Participant

    Getting to this point took roughly 4 episodes of the X-Files on Netflix, including posting the thread as I went.

    #38229
    Max
    Participant

    I started blocking in the body the other day, but didn’t get super far. Maya has layer functionality just like photoshop and most other image editing software, so I like to put the different parts on different layers and hide them to get them out of the way. This soft-surface stuff I find is where you really need to pay attention to your polyflow, because if you have bad geometry it will deform in crazy ways on your animated character. The shoulders and elbows with the attendant wrinkles are going to be the parts I’ll be concerned about as we get further along:

    In general you want to make sure your polygons are all fairly uniform in size, but in areas where your model deforms you’ll want to make sure you have more polygon resolution to avoid funny pinching and such. You’ll find most of your geometry in the face, joints, and hands typically on character models.

    #38487
    M
    Participant

    I hope you’re still doing this, I can’t be the only one whose really digging this post.

    Looking forward to texturing specifically.

    #38488
    Max
    Participant

    Ha ha, I’m kind of thinking you might be, @M. I haven’t done much work on it since that last post, but I intend to finish it. I’ve just got a lot of projects gong on (not least of which is finding full time work), so my spare time is limited.

    #38489
    Max
    Participant

    In lieu of an actual update, I’ll drop this wireframe comparison of the original Lara Croft model from Tomb Raider side by side with a more modern version.

    What you’ll notice on the original image is that PS1 didn’t have soft-binding capability, so you had to actually use separate objects for the torso, forearm, bicep, etc. This is very apparent in early 3d games like Virtua Fighter 1 where you can sometimes see the joints like a Pinocchio puppet. You’ll see the overlapping polys in the joints if you look. That character only has 300 tris in the whole model.

    In the 2007 model you can see what I was describing with the amount of geometry present in her face to allow for smooth deformation.

    The term “soft binding” describes attaching a model to a skeleton in such a way that it can deform when the skeleton is moved. The other way to do that is with rigid binding, where each thing is 100% attached to a particular joint and there is no flexing. It works well for vehicles and robots, but at one time it was all you had.

    #38525
    Max
    Participant

    I did some work on it tonight after I got home just so it wouldn’t get too stagnant. Here is the current state of the body. He still needs hands and a neck, and I’m going to make the flap over the jacket as a separate piece of geometry:

    I’m not sure how hi-poly I want this character to be just yet. I’ve added some extra geometry to the joints, but I won’t really know until I rig it and try to pose him around whether or not it’ll need more.

    #38533
    Max
    Participant

    I gave him a collar for his jacket that isn’t really visible in this shot because of the helmet. I also made the flap for his chest. I did that by making a flat cube, then positioning it so the right most edge was in the center of the model. Then I extruded to the left, making sure the contours of the flap matched what was present in the existing body before doing another extrude. I deleted the back faces since you’ll never see them.

    #38745
    Max
    Participant

    So now that it’s time for hands, I thought I would address the “how much of that can be re-used?” question from earlier. Hands are complex, and I don’t really feel like making new ones from scratch. So what I did was import the Zombie model that I had laying around and make sure the model scales were the same. I then cut all the faces off of the zombie that weren’t on the hand I wanted, and did the necessary massaging so that it would look more appropriate to a Rocketeer than a Zombie:

    Anything you have floating around in the scene you import will come in, so make sure you clear it all out to avoid bloating your scene (hidden geometry, cameras, layers, lights, materials, etc.)

    Once I had the one hand, I copied the hand and did a negative scale to send it over to the other side of the model. This is a handy trick for mirroring something into the opposite side of the model, but there are some things Maya does that you’ll want to be aware of. You can use the Mirror Geometry tool, but that doesn’t give you a new object like you may sometimes want. When you combine objects in Maya and then separate them, the manipulator pivot goes back to the scene origin 0,0,0, so I’ll usually do that with the object I’m trying to dupe. Then I ctrl+d to duplicate, and then set the Scale attribute (X in this case) to -1 to send it over to the other side reversed. Doing that has the side effect of reversing the normals, which basically means that the outer faces are now considered “back faces.” You can check this in maya by doing Display->Ploygons->Face Normals with the object selected, and it’ll display little green lines emitting from the direction of the normals (you’ll need to do the same thing again to make them go away):

    If the normals don’t look right, you can reverse them (which I have done here), or conform them if some are facing one way and some are facing another. It can be tough to eyeball it when you have a complex model, so do it prior to adding in a bunch of resolution if you can. Make sure you select the hand and Freeze Transformations to strip the negative scale off your geometry. Funny things like that have a way of biting you later if they end up hanging around.

    Now that we have our hands (I haven’t sewn them into the sleeves, I’m going to see if I can get away with not doing it at the rigging phase), this is what he looks like:

    #38751
    Max
    Participant

    here’s the rocket pack. I extruded the straps out of the character’s body, since I don’t intend for him to be able to take it off. My concept art doesn’t have a holster for the pistol, so he’ll have to just hold it.

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