More on Joint Orientation

Can of worm about interpolation done by computer:
When you animate in Local mode: if you ever touched gimbal or first axis rotation (they have an angle), then all your rotation along a local axis will not be interpolated nicely (so that it follows the rotation along that axis) anymore. This is one more reason that You need Constant interpolation (Step Tangents) when you are blocking out. once you do linear with so few keys, all the curves will be messed up.

The Joint Orientation (needs to be confirmed, VERY VERY IMPORTANT)
Orientation axis of polygon or joint have one thing in common, it “makes stuff rotate” but keep the rotation values ZERO.
For polygons  Rotate Axis in the transform node is the same as the local translation axis. You may go into transform node and change the rotation axis, It is apparently only altering the geometry behavior, the local or gimbal rotation handle still points the same way, but the geometry is skewed, so that Object mode of translation will change, scale will change

For Joint, we are given a new tab inside the Transform node. the Joint Orient,  Joint Orient DOES modify the local or gimbal rotation direction, But in the process you might have changed x axis not to be twist axis anymore. Joint Orient can be accessed from the ctrlA, or can use component mode’s “?” button to rotate manually (MOST VISUAL), or the joint Orient tool in skeleton-> to set x as twist.

Best way: orient constrain to the desired degree, then ctrlX the rotation value to joint orientation. so that R is set to all 0 and joint orientation is set to the desired value.Or better: just unparent the child joint, the duplicate the parent joint, then move the duplicated joint in object mode, as the x will point to the child joint. (make sure that there are no rotation value on any joints)
Or Even Better: Insert Joint tool from maya, it will auto align the x axis.

What I did for the arm:
drew bones using v snap, so that I don’t need to manual rotate Joint Orient. I created 3 joints to account for true non gimbal twist. change to zxy, I use a curve, change to zxy,  reorient rotate axis, with f8, so that z and y rotation are along the oblong, and x is the twist, there might be + – sign problems.  Easier snap to elbow, match orientation. Use a null, do the same and parent curve to null to nullify the rotation values.

NOW, IK can’t work, and IK will move all the the joints, I want certain joints unaffected.
Apparently 3 joints arm will not work, as the Ik solver will freak out. There will not be true twist. and rotation will be

Problems:1 geo is in IK handle now, but Geo is not rotating With the joint. it is normal right?
2. IK  to FK, FK to IK transition. what to key,
3. We have a snap problem in the 3 joint arm (first joint zxy, all enable, second join xyz, yz limit to 0),  as 3 joint will have multiple planes to define, I hope the extreme short distance between them will solve that problem, and there is a pole vector problem, as it is aligned with the first joint, But the principle appearance is determined by the true twist.  how to manipulate pole vector to make sure that it is pointing to the apparent?
3, how come we can move Fk and Ik at the same time?
4, the hypershade, hyperArchy twist is interesting, but the premises is that the twist is the true twist right?
interestingly Enough:we can use that parent tool to combine none polygons.

Rigging the Humerus

How to set up the Humerus:
guy_v1, The Toy FIgure approach:
rotation Order yzx. x is twist, z is minus forward (pointing downwards so that forward z is positive angle)
This is just like the toy figure (without the twist), or the tank turret (with the tank hang tail up and nose down)

Adam SaleAndFinal (for simple stick man):
X is always the twist,THEN x HAS to be the Gimbal. Z is the forward position
where the solver axis lies. y is the updown. zxy.
Can cover most space with least amount of gimbal.

Norman approach or general approach:
The problem with this is that: x will not always be the True twist.
THe first order of rotation is always the True rotation, because every other rotation will
bring first order along.

Thus assigning twist to x axis and make x to the first order is biologically correct.
that’s NOrman’s approach. xzy, z is forward/gimbal, y is down
shoulder will take care of forward gimbalz in arms using xyz, z (pointing downwards, so that forward z rotation will be positive)is forward, x is twirst, y is gimbalDown

As you can see lastOrder and gimbal compensate each other in shoulder and arms.
This doesn’t mean a Letter to letter wise compensate, this means: directional compensate
so forward gimbal will be compensated by a forward lastOrder. xyz’s are irrelavent but only bound by the convention that x must point at the twist.

My own thought (the toy figure approach):
the toy figure approach:
draw your bone from top view, then orient joint xyz (firstOrder pointing at the bone), 2nd ax: +z (make y pointing at +z so it is up and down), Set rotation order yzx, like the toy. then use another joint soley deal with True twist.
Brilliant, as true twist have to sacrifice firstOrder, then you will have a gimbal axis controlling a major degree of rotation.
comment: true twist will never work, as the IK solver will not work on this setup. There will be a snap.

(the true human approach):
Euler rotation is the limiting factor, we will never get Local mode like rotation.
human arm do not swing half of a sphere and most of our arm motions are quite resitricted to the frontal cone.
Thus don’t rig in T pose,  Rig in forward v pose.

My Final Demo Reel

My demo reel idea started completely opposite as how a normal demo reel would start. Normally for a demo reel, a person would develope a story, design character for the stories, then worry about modeling the character, after that try to figure out how to rig and animate the character. My demo reel started in the opposite direction. I started with couple of rig setups, the complexion of those rigs just appeals to my nature. those are rigs for arms with twisting capability and rigs for shoulders that move lots of bones and muscles around. I proceeded to design the body parts to work with those rigs. After that I proceeded to fill in the rest of body. The end result looks like a female cyborg:

Now I have a blocked out character with no background story serves no purpose in a story that doesn’t even exist yet. It only serves to show off the rig. I somehow managed to came up a rough idea about what kind of world the cyborg should live in: inside the virtual world of our personal computer. The cyborg would be a… anti virus software of some kind. And the story would be about the cyborg fighting computer virus maybe. I went through several instructors to get feedback on the character design, after revision, I landed on this:

 

Face Flows in modeling:

in our modeling is relatively easy when we keep meshes separate. when we try to model a human with every

thing in the same mesh, things can become hard. When we try to model a human mesh with edge flows that follows the muscle structure things can become very hard.  when we start with a mesh with horizontal and vertical face flows, it is hard to diverge the  face flow to a another direction. extrude will create a diverting structure within faces, but we can’t always use extrude to create such kind of face flow.

I made a animated gif  depicting the procedure of diverting a face flow.

More on Maya’s UV unwrapping.

I never knew how Maya stores the unwrapping information. it is not stored in a node, well, not a visible, easy accessible node at least. it’s not in the transform, not in the geo/mesh node. XSI, however, offers somehow a new perspective on this subject. The UV map is stored inside the cluster folder served as an attachment. XSI has the equivalent of transform and geo node in an object’s explorer, and the UV map is not stored there. So apparently the UVs are treated in a similar manner.

My conclusion of how UV and texture works is near complete. Here it goes: UV mapping might be Object based when stored, but you make it in face basis. Or simpler, JUST REMEBER: Faces. Those faces can be selected in any manner you want, from the same object, or from multiple objects.

on PolyMesh.

My thoughts are not organized at this moment, as I don’t have the proper knowledge in dealing this stuff. I just have a haunch that something big can get out of this.

we just started to learn how to model a human. it’s about edgeloops, it’s about how to use 4 sided shapes only to describe the subtle cross contours on a human body.

seemly simple but sometimes the task is quite mind boggling. it is an experience based task, but it just appears to me to be purely mathematical. I have the vague feeling that 1 or 2 Master students given 3 years can come up with an algorithm to create ideal meshes for any given muscle structure. Some topological geometry related math department

the problem of Triangles and 5 sides. those shapes are the most common. how to get ride of them, what kind of topology are we getting after we have get rid of them. I somehow have a homebrew method to get rid of them. the method is to create a tri-edge point inside of the triangle or pentagon, with 3 edges rest on the edges of the trangle or pentagon, then those edges will go through edge loops and tigh up somewhere.

The approach should be quite sound mathamatically. Take the 5sides for example. we need to get integer number of 4 sides inside it. thus we need 8 or 12 edges out of those 5 edges. any edge we introduce with actually introduce 3 extra edges or 4. we can introduce an extra point to split an edge. we can’t introduce point to point edge, that will form a triangle.  we can’t introduce edge to edge edges, as itself will create an extra 4 sides,  5+4n will never be integer number of 4. we can only introduce point to edge edge. that will create 3 extra edges due to spliting an exsiting edge, and creating an edge shared by two polygons.  so 3+3×3=12 or 3+1=4, thus you will need to have 1 or 3 extra edges to get right of a triangle.

the problem can also be looked into from the vertex point of view. a vertex not on the boundaries of a mesh should have 4 edges connected to it. so if a 5 edge point appears, that will happen when you are connecting two concentric  endge loops, there must be a 3 edge connection somewhere in the same mesh to compensate, tide it up in a pole, or snuff it inside a 3 edge structure.

Maya’s UV unwrap. Three approaches

First Approach:  Manual Cut then unfold, …then pray

plannar projection first, the purpose of that is to get an UV, no matter  how messed up it is,  so that  it does not have any cuts. you need to manually cut up your edges from the object space. After that, pick your pieces (they should be blue red or purple due to the mess of overlapping) and unfold (hint:you can select UVs on the geometry if the uvs are too much tangled). Unfold is powerful, we can use the unfold tool icon, or the unfold tool in the uv editor menu.

The key to the unfold tools is the pin option. unfold icon will always pin the unselected (so you can RC menu to shellborder, then ctrl select the whole UV again the select all the UVS except the shell border). The unfold tool in menu gives you more options. it’s a good practice to tackle a really Fooked up UV mess by pinning two points that are close to the poles of a geo and unfold the rest.

Second Approach: Automatic Unwrap, explode , then move/sew … then pray

you can Automatic mapping first, pick the biggest piece out, explode the rest by using the cut edge tool. Now,  select all the rest small individual pieces, go to the object world, see where those little pieces are, DESELECT the seams you would normally manually to cut. Move and sew those pieces, they will fall in line with the big piece, with those deselected edges unsewed.

When you are only unwarpping half of a geo, expecting a symmetry duplicate to the other half, make sure the contact edge is straight in your UV space.

Third Approach (best Approach): Just  pray

The real Hello World (it’s about Time Management as required in the course outline)

What is Time Management to me

English is not my mother tongue, and, I have this natural “anti-affinity” towards language and literature as a whole. As the result, I totally misunderstood what Time Management was. I thought it was only for those blue blood CEOs or IQ250 particle physicists to be more … transcendent as they already are. They have too much to do, yet life is equal and short; well, shorter for them, due to their workaholic-ism.  They really have to have the golden fingers that pick the exact right tasks at the exact time to accomplish them with the exact given time period.

My Take on Time Management

Apparently. Time Management is only a myth. I think the title is a bit misleading too, we are not actually managing time. Oh well, with a PHD  specializing in the study of General Relativity and enough energy … and 10 trillion dollar in budget, we can indeed manage time a bit. But,  even the introduction of the introductory books pertaining to those subjects will bore most of us to death. Time Management is about managing ourselves, time functions as thresh holds or measurement standards. Most people have time management problem is not that they don’t have enough time to do things, it is not that they are not given enough time to do things, it is that they didn’t give themselves enough time to do things. Time Management for me is more about “stop playing, start working”, instead of actually increasing efficiency yet. And that should be the first step. Prioritize, Good Planing, Keeping Track… well those are valid points. But I prefer to start with the proper motivation and  the sense of urgency. As they are the fundamentals that we can start and finish any long arduous tasks.

Motivation, the proper ones

Be aware the words I  used, as I have chosen them carefully. “Proper” motivation and “Sense” of urgency. We sit in the offices and classrooms like everyone else, but there are myriads of reasons why we are doing so.  But the right purpose makes us great in what we do. There are patriots, there are mercenaries, but a Nation is founded by the former. When the route a person has taken is only a tool or ladder for something else. No matter how noble that “something else” is, the person may work diligently in that route, but he may never excel in that route. And most likely an easier route will open up during the course. Eventually it comes down to what is right and what is easy.

Sense of urgency makes us more alarm and crisp. With that sense, we will automatically stop trifling with trivial or indulging ourselves with meaningless entertainments and start prioritizing the important stuff first. Take an exame situation for example, I don’t think we will doodle on the paper or text messaging a friend during that. And we have to consciously pick the questions we can answer within given time and give up those hard questions that will simply be way too time consuming for us to finish.  mere urgent deadlines that has little appear to us will only make us hate the job and rush the tasks, thus compromising the quality of the work. Too much of it maybe stressful, but in a long run it saves more headaches.

Well, apparently I will need alot more space and time to write about this Time Management. Maybe next time then.

Hello World

First Post should have no topic. It is about random stuff from my brain

First post is about mind wandering, ideas will flow through as my trillions of synapses fires in a random manner. As the random action potentials searching through the crevices of odd and dusted connections, As the synapses sending new “shopping lists” to each other and to their silent silent partners, the glial cells; unwrapping their own chromosomes searching through a tediously long chain of DNA and starting manufacturing the necessary proteins to manufacture more proteins and enzymes thus to manufacture other stuff and so on and so forth…

Brian is amazing. Life is more

Quite amazing, isn’t it. Life itself. Either it was the God, or it was the Evolution, whichever floats your boat, Life is such a grandeur. And we were so awed and amazed by it by just knowing one format, a carbon based one that lived on earth.  Life itself is a word, a word that is 66 times the length of bible for most of creatures, I mean, it is not just Human. I am talking about DNA. it is Digital, it is the blue print, it is not perfect I know, it is selfish, it does no good to the organisms but benefiting themselves. for God’s sake even the genes you inherit from your mom and dad are antagonistic to each other.

Dolly the Sheep

Remember Dolly? the cloned ship in 1997, well, the thing is, we, including the researchers did Dolly, still don’t know today how they circumvent the inprinting problem for mammals that was raised due to the antagonistic yet cooperative  genes from mom and dad.

Species wise, we ain’t doing too well

Just look at our own kingdom, arthropods are more numerous in their family and vastly outnumber us in bio mass, they eat each other, sure, but they coexists quite well. More amazingly,  they developed this symbianonic relationship with another kingdom called plant, that relationship is so successful they made the “flower plants” the king of the hill.

How about other kingdoms, bacterias. well I m still fuzzy about the bacterias we see today, I am not sure  either they predate “us” ( eukaryotes, the dudes with a nucleus in their cell or cells). Yeah sure, we like things better organized. so you might want all the information that you will use to make a copy of yourself saved in a secure location. well, we do that, we roll them up in 23 nicely packed blobs called chromosomes (before 1952, we thought there were 24, yes, we had a photo with 23 of them, but we just counted that there were 24.  sowhat, we were biologists, we don’t need to do our math)

Something about bacteria, order and chaos theory

back to bacteria, most of them don’t use RNA to translate DNA anymore, they do the whole transcription and translation in one go. simple efficient and error proof. it is less organized. being less organized is BEAUTIFUL. we talk about “Gaussians” all the time. I don’t know what you do, if you use a computer and work inside an office, you heard of the word “Gaussian”. Gaussian distribution, White Gaussian noise, Gaussian this and Gaussian that. Remember Gaussian is an approximation, it does good to the naked eyes in a pie chart or histogram. it simplify the countless lives of Unversity and Highschool students, since Gaussian functions intergrate differentiate easily and well known. Gaussian is not real. it is not how nature works, at higher momentum (differentiated more times), the function curve goes flat. Nature DOES not go flat, Nature is random, it is not infinitely predictable , BUT, Nature is Deterministic. Then came the catastrophy theory, and then it came the Chaos theory.

1925, someone proved that you can’t know the current status to infinite accuracy, it is not the problem of the measurement, it is the problem of quantum theory. PROBABILITIES, that’s the new buzzword.We know that rule today as the “Uncertainty principle” or the “law of average”.

Albert Einstein was a great guy, you know the E=mc2 guy.  But he never trusted the Copenhagen interpretation (the quantum mechanics you heard or learnt in colledge level, excluding real physics students), He went to his graves without fully accepting quantum mechanics (a science about electrons bozons and bonbons). However the holy grail of physics today is to unite his General Relativity and quantum mechanics, God willing, I shall live until that day to see someone actually do it. And Steven Hawking is not the guy to tackle the problem. He is too much into the Macro world.

It is not finished, the mind continues to wander, but that’s the point of the first post.

getting tired, and the inaccuracies in my mumbling is now even beyond my standard. it must ends now.

the proper Hello World

Hello World, and me

“Hello World”, ahh well, that 2 words 4 syllables phrase has been accompanying me since my “adventures” in this English speaking country started. (and the English speaking country is United States of Canada). I was in an Electrical Engineering school for 4 years, actually 5 years,  if I want to be precise. But I got into a lot of computer and software stuff. I know, when ” Electrical Engineering” flashes through people mind, they think of the Tesla coils and microwave ovens. well, it’s not the case really, because Tesla coils and microwave ovens are two concrete objects. we learnt something fundamental and seldom venture into anything that is practical. We might have go through some of the practical applications of the theories, but they will never exame you on the “practical stuff” that dwells in the backwaters of the textbook. if a law is not enforced, it is just a piece of paper, if material is not exam-ed chool, it will just flow through students’ ears and never leave a mark.

we learnt in the university is very arcane. And old, very very old. Let me “accurately” exaggerate this point further: the thing you have learnt in you high school is pre middle age mostly. the thing we learnt in University is mostly pre-WWII, well, at least for civil and mechanical Engineering students. Being old isn’t bad,  as the fundamentals of any field is solid and immutable for ages to come. they are always depend upon, they set up your way of thinking for the  rest of your journey. The tools we use to learn is improving and the entire computer and programming business is totally man-made and post WWII, or post-1970.

“Hello  World” is a computer science term. it is the first program you will do, it is a short piece of code that will display “Hello World” on you computer screen (or somewhere on your screen, may that be a console window, in txt pad, a pop up message or a text field in some window). It is a brutal simple piece of code, and it is usually accomplished by a single line of instruction. But there are other fuzzes or setups you have to do to enable that single line of instruction to be understood by the computer. And the comparing the different setups necessary in different programming languages reflects the general trend computer science is progressing. Computer science is no longer an esoteric specialty that only the acute can master and learn, “programmer” is no longer a title that is distance to ordinary people.

getting boring, getting pointless, terminating now.