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About Kryzon

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  1. Why do quaternion look-at's flip?

    Changing the "rotation mode" in Blender (with all the different permutations of Euler axes, as well as a quaternion mode) leads to visually different results in the aim constraints, so now I have more room for experimentation. Thanks again for the help.
  2. 2D Climb Wall Question

    I apologize for the font of Heading 2 size on my post... the post editor for this forum on mobile sucks
  3. Why do quaternion look-at's flip?

    This is interesting. Are you saying that there's an order of Euler angles that can let you roll a bone along its length axis, without changing the aim? (I remember this happening before)
  4. Why do quaternion look-at's flip?

    Thanks for all the info guys, I'm going through it right now. I like this statement from that "Quaternion help" thread: "you also need an up vector or else you have infinite number of solutions." That makes sense! From that game engine clip, when the target goes near the up-axis of the source, the source must have trouble aligning its up vector with the world up vector. In case of aim constraints (for 3D rigs and animation) the Maya docs recommend animating the up vector of the source object. Maybe this can be done with a driven expression -- changing a property of an object based on the properties of other objects (such as how high or low the target is). - - - - - - The rig parts that need this aim constraint are the shoulders and thighs: ball-socket type joints with the possibility of roll. It's not simple to explain, but the way that real muscle masses and skin are deformed by bones, if you simply share the shoulder skin influence between the upper arm bone and the clavicle bone, the entire shoulder rolls along with the upper arm in a wrong way unlike real life. So a way to fix this is to use a helper bone that aims the elbow but keeps its up vector still, so you can get realistic twisting on the shoulder area (see how the upper arm can be subdivided in two bones, one for the shoulder and another for the upper arm roll): The downside of this method is that, because of the aim constraint, the shoulders do that up-vector fail when the arms are all the way up or down, (the twitch from that GIF on the first post).
  5. 2D Climb Wall Question

    I remember this from MUGEN, you had to set points called "axes" to let the engine know where's the pivot of each sprite frame while jumping, kicking etc. This way you can control how the sprite slides around its location, how it is offset when drawn. In case of a climb, for some frames you could place the axis on the character's hands so they stay still in place while the rest of the body moves as the character lifts themselves up. The sprite bitmap can be cropped \ trimmed out of all transparent pixels to save memory, since the axis point is abstract and you can do it in code, it's just an offset.
  6. Why do quaternion look-at's flip?

    Hi @Scouting Ninja, thanks for looking into it. I think there's no slerp in there (I didn't write the code, but I took it from an old but good game engine to rule out any implementation errors). From what I understood the function takes the (world) source -> target vector and creates a quaternion from it, and then sets it as the (world) rotation of the source object, effectively making it point \ aim along the vector to the other object. But that twisting of the red and blue axes can be seen everywhere, not just in that engine (Blender's Track To and Damped Track, Maya's Aim constraint etc.). Now that I searched with different terms, it's briefly mentioned in Maya's docs: https://knowledge.autodesk.com/support/maya-lt/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU/MayaLT/files/CSCo-Prevent-rolling-effects-for-aim-constraints-htm.html I'm wondering if there isn't some space-conversion, hierarchy-arrangement or axis-switching trick to avoid this thing. Any help is appreciated.
  7. The green axis of the gizmo is pointing at the ball. The red and blue axes twitch when the ball passes a certain point (ignore the discontinuity of the GIF): This is from a simple game engine so it's easier to analyse, but I've seen this behaviour in plenty of other cases (including animation software, with aim constraints). Is there a way to avoid this flipping? Is there a method of rotation that doesn't need to adjust the blue and red axes, where it just points the green to the target and the other axes can freely rotate and accumulate rotation, rather than having to do this "reset"? I'm asking this as an animation character rigger, working with some bones with look-at constraints that have this same flipping \ twitching behaviour. For reference, the source code of the look-at from the image: The look-at function (from here): void bbPointEntity( Entity *e,Entity *t,float roll ){ if( debug ){ debugEntity(e);debugEntity(t); } Vector v=t->getWorldTform().v-e->getWorldTform().v; e->setWorldRotation( rotationQuat( v.pitch(),v.yaw(),roll*dtor ) ); } From that, the v.pitch() and v.yaw() methods (from here): float yaw()const{ return -atan2f( x,z ); } float pitch()const{ return -atan2f( y,sqrtf( x*x+z*z ) ); } ...and the rotationQuat function that creates the quaternion (from here and here): inline Quat pitchQuat( float p ){ return Quat( cosf(p/-2),Vector( sinf(p/-2),0,0 ) ); } inline Quat yawQuat( float y ){ return Quat( cosf(y/2),Vector( 0,sinf(y/2),0 ) ); } inline Quat rollQuat( float r ){ return Quat( cosf(r/-2),Vector( 0,0,sinf(r/-2) ) ); } (...) Quat rotationQuat( float p,float y,float r ){ return yawQuat(y)*pitchQuat(p)*rollQuat(r); }
  8. Bitmap Graphic Needs Smoothing

    Thank you for sharing. Your Photoshop scaling method is interesting. When you compare both versions (letsenhance vs ps), they have some slight shape differences (at the outer edges of the ears, for example). One of these versions might be more faithful to your original design (the one named Original), in case you downscaled it to make that thumbnail, so this is a way to tell which method is best. If you drew it small like that then I don't think there's a reliable way to know which method is best, it's subjective. I'm not sure how they trained their AI. I would guess they took HD photos, downscaled them and then told the AI "to take this low-res image input and generate this HD image output". You do that a lot of times until you have a generic model for that AI to upscale small digital photos. Maybe their model works best with photography (pictures taken with digital cameras), rather than man-made images. For example, someone trained an AI model to specifically upscale anime-style images: http://waifu2x.udp.jp/
  9. Bitmap Graphic Needs Smoothing

    Without you posting any proof I'm gonna have to call your bluff. Someone else compared it with standard cubic resampling (using Photoshop, but cubic resampling is present in almost any image editor one can get). They had a different experience than yours. "Photoshop 16x bicubic:" "letsenhance.io 16x (ran twice):"
  10. Bitmap Graphic Needs Smoothing

    The cutting edge tech in image resizing is using neural networks: https://letsenhance.io
  11. I am looking for this tutorial (2D art)

    Can you post what you've done? I feel it'd be much easier to give feedback.
  12. Best way to create terrain/assets for 3D JRPG?

    I would categorise that Tales of Vesperia style as "low poly hand-painted". Everything you do with a graphics tablet is technically "hand-painted", but when people use this term they usually mean a model that is textured with only a diffuse \ albedo texture that was painted using mostly noiseless brushes, such as a hard round brush, and little to no post-processing or filtering. It has a specific stylised clean look. It's a very popular style and you can find plenty of stuff (on how to create your own assets) on Pinterest (you need a free account to see everything), Youtube etc.
  13. Day-night cycle colors

    If you're technically inclined, there's this website full of info on computer graphics -- including the sky-scaterring phenomenon that's related to the colours of a day-night cycle: http://www.scratchapixel.com/lessons/procedural-generation-virtual-worlds/simulating-sky
  14. Which color picker do you prefer?

    I prefer this one, the saturation-value square inscribed in a circular hue border: Couple of benefits that I think it has: - Slightly bigger picking area than the triangle variant. - The square shape is aligned with the saturation and value axes, so it's more intuitive to use than the triangle with its tilted vertex axes.
  15. Need Help Choosing Art Style

    If you're in doubt of what style to go with, here's a suggestion: flip a coin. If it's heads you go with the comic style and if it's tails you go with the hand-painted style. If you flip the coin and go "oh, no..." (disappointed at the result), then you finally found out which style you really prefer. Going a different way, though, you could pick the style that's enjoyable and easy to work with so you can move on and make your game -- since you worked with both styles, you're the best person to gauge which one has these qualities. One thing that I would do differently is to make a full mock-up of a game screen, including characters, ui elements etc. Maybe one of these styles will clash with something in an unexpected way, so you should give yourself more visual information to make a good decision.
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