i am simulating a tennis game and i have a tennis player which i made with 3d max and it has
frames for each movement and exported it as fbx model but i don't know how to use this frames to animate the player inside the xna code .
thanks
In the Skinned Model Sample and related educational material you will find how to do character animation using XNA.
The main trick is "rigging" the model for animation using a set of bones and then specifying animations in terms of those bones. This way the animations can be bound to any other model that has the same bone structure, and animations can be blended (say, swing the racket and run at the same time).
Be warned, this is a fairly advanced technique, as it requires quite a lot of work from the programmer and the artist to get right.
Related
Is it possible to import a virtual lamp object into the AR scene, that projects a light cone, which illuminates the surrounding space in the room and the real objects in it, e.g. a table, floor, walls?
For ARKit, I found this SO post.
For ARCore, there is an example of relighting technique. And this source code.
I have also been suggested that post-processing can be used to brighten the whole scene.
However, these examples are from a while ago and perhaps threre is a newer or a more straight forward solution to this problem?
At the low level, RealityKit is only responsible for rendering virtual objects and overlaying them on top of the camera frame.
If you want to illuminate the real scene, you need to post-process the camera frame.
Here are some tutorials on how to do post-processing:
Tutorial1⃣️
Tutorial2⃣️
If all you need is an effect like This , then all you need to do is add a CGImage-based post-processing effect for the virtual object (lights).
More specifically, add a bloom filter to the rendered image(You can also simulate bloom filters with Gaussian blur).
In this way, the code is all around UIImage and CGImage, so it's pretty simple😎
If you want to be more realistic, consider using the depth map provided by LiDAR to calculate which areas can be illuminated for a more detailed brightness.
Or If you're a true explorer, you can use Metal to create a real world Digital Twin point cloud in real time to simulate occlusion of light.
There's nothing new in relighting techniques based on 3D compositing principles in 2021. At the moment, when you're working with RealityKit or SceneKit, you have to personally implement the relighting functionality with the help of two additional render passes (RGB pass is always needed) - Normals pass and PointPosition pass. Both AOVs must be 32-bit.
However, in the near future, when Apple engineers finally implement texture capturing in Scene Reconstruction – any inexperienced AR developer will be able to apply a relighting procedure.
Watch this Vimeo Video to find out how relighting can be achieved in The Foundry NUKE.
A crucial point here, when implementing the Relighting effect, is the presence of a LiDAR scanner (or iToF sensor if you're using ARCore). In other words, today's relighting solution for iOS is Metal + RealityKit.
I’m interested in the issue of data processing from TrueDepth Camera. It is necessary to obtain the data of a person’s face, build a 3D model of the face and save this model in an .obj file.
Since in the 3D model needed presence of the person’s eyes and teeth, then ARKit / SceneKit is not suitable, because ARKit / SceneKit do not fill these areas with data.
But with the help of the SceneKit.ModelIO library, I managed to export ARSCNView.scene (type SCNScene) in the .obj format.
I tried to take this project as a basis:
https://developer.apple.com/documentation/avfoundation/cameras_and_media_capture/streaming_depth_data_from_the_truedepth_camera
In this project, working with TrueDepth Camera is done using Metal, but if I'm not mistaken, MTKView, rendered using Metal, is not a 3D model and cannot be exported as .obj.
Please tell me if there is a way to export MTKView to SCNScene or directly to .obj?
If there is no such method, then how to make a 3D model from AVDepthData?
Thanks.
It's possible to make a 3D model from AVDepthData, but that probably isn't what you want. One depth buffer is just that — a 2D array of pixel distance-from-camera values. So the only "model" you're getting from that isn't very 3D; it's just a height map. That means you can't look at it from the side and see contours that you couldn't have seen from the front. (The "Using Depth Data" sample code attached to the WWDC 2017 talk on depth photography shows an example of this.)
If you want more of a truly-3D "model", akin to what ARKit offers, you need to be doing the work that ARKit does — using multiple color and depth frames over time, along with a machine learning system trained to understand human faces (and hardware optimized for running that system quickly). You might not find doing that yourself to be a viable option...
It is possible to get an exportable model out of ARKit using Model I/O. The outline of the code you'd need goes something like this:
Get ARFaceGeometry from a face tracking session.
Create MDLMeshBuffers from the face geometry's vertices, textureCoordinates, and triangleIndices arrays. (Apple notes the texture coordinate and triangle index arrays never change, so you only need to create those once — vertices you have to update every time you get a new frame.)
Create a MDLSubmesh from the index buffer, and a MDLMesh from the submesh plus vertex and texture coordinate buffers. (Optionally, use MDLMesh functions to generate a vertex normals buffer after creating the mesh.)
Create an empty MDLAsset and add the mesh to it.
Export the MDLAsset to a URL (providing a URL with the .obj file extension so that it infers the format you want to export).
That sequence doesn't require SceneKit (or Metal, or any ability to display the mesh) at all, which might prove useful depending on your need. If you do want to involve SceneKit and Metal you can probably skip a few steps:
Create ARSCNFaceGeometry on your Metal device and pass it an ARFaceGeometry from a face tracking session.
Use MDLMesh(scnGeometry:) to get a Model I/O representation of that geometry, then follow steps 4-5 above to export it to an .obj file.
Any way you slice it, though... if it's a strong requirement to model eyes and teeth, none of the Apple-provided options will help you because none of them do that. So, some food for thought:
Consider whether that's a strong requirement?
Replicate all of Apple's work to do your own face-model inference from color + depth image sequences?
Cheat on eye modeling using spheres centered according to the leftEyeTransform/rightEyeTransform reported by ARKit?
Cheat on teeth modeling using a pre-made model of teeth, composed with the ARKit-provided face geometry for display? (Articulate your inner-jaw model with a single open-shut joint and use ARKit's blendShapes[.jawOpen] to animate it alongside the face.)
So.
After many years of iOS development I said it's time to try to do a little game for myself. Now I chose to do it using Apple's SceneKit since it looks like it provides everything I need.
My problem is that I've stumbled upon a huge problem (for me) and searching on Google doesn't yeld any results.
Any idea how do I go about having an object (a sphere for that matter) that deforms itself, say, because of a gravitational force. So basically it should squash on impact with the ground.
Or, how do I go about deforming it when it collides with other spheres, like a soft beach ball would?
Any starting point along those lines would be helpful.
I can post my code here, but I'm afraid it has nothing to do with my problem since I really don't know where to start.
Thanks!
Update
After doing a bit more reading I think that what I want could be doable with Vertex Shaders. Is that a right path to follow?
For complicated animations, you'll generally be better off using a 3D modeling tool like Blender, Maya, or Cheetah3D to build the body and construct the animation. Those tools let you think at a higher level of abstraction. Then you can export that model to Collada (DAE) format and then import it into SceneKit.
https://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Basic_Animation/Bounce has a tutorial on building a deforming, bouncing ball using Blender.
SceneKit only does physics using rigid bodies. If you want something to deform, you would have to do it yourself.
It is probably because SceneKit has no way of knowing how an object should be deformed. Should it just compress, should it compress in one direction and expand in all others to preserve it's volume, should only part of the model compress and the rest stay rigid (like the tires on a car).
What you could try is wait for a collision to occur and do the following
calculate and store the velocity after the bounce
disable collision checking on the object
run an animation for the "squash"
enable collision checking on the object
apply the calculated velocity
It will be entirely up to you how real or cartoony you want to make the bounce look.
I have just delved into the world of Metal, and I thought that I'd got the hang of it! But then it occurred to me that if I wanted to make a game, then static objects moving around a screen wouldn't suffice. So my question is, 'Is it possible to create animations for models with Metal?'
I have looked at using other APIs, such as SpriteKit, and SceneKit, but I found that they do not support shaders, and are not as powerful as Metal.
The only way that I can think about how I would go about this, is by creating 60 different models, and then loading each one one after the other, to give a 'stop-motion' kind of effect, but I think that this would probably be incredibly inefficient, and was hoping that there was an easier answer?
Thanks a lot!
Yes, there are other, more efficient ways to do animation. But before getting into that, a warning: it really looks like you're barking up the wrong tree here.
Metal is a (conceptually) very low-level interface. You use Metal to talk (almost) directly to the GPU, so to work with it you need to think (sort of) like a GPU: in terms of data buffers, vertex transformations, etc. You seem to be working at a much higher conceptual level, so you're probably better served by one of the high-level game engines: SpriteKit for 2D or SceneKit for 3D. (Or a third party engine like Cocos or Unity.) Metal, on the other hand, is better suited for building those game engines.
SpriteKit and SceneKit do support shaders. Look at SKShader and SCNShadable in the docs (and be sure to click the "More" links to read the full overviews). SceneKit also supports character animations (aka skeletal animation aka skinning): typically one designs and rigs a model for animation in an external authoring tool (Maya, Blender, etc), then uses SceneKit to work with the animations at run time.
It is possible to do things like GPU-based skeletal animation in Metal. But I haven't seen any tutorials or similar written about it yet, probably because Metal is such a new technology. Fundamentally, though, it'd be based on the same sorts of techniques you'd use for skeletal animation in OpenGL or Direct3D — and much has been written about animation for those technologies. If you're willing to invest the time and energy to work at a low level, adapting the subject matter from GL/D3D tutorials is relatively easy.
You can do skeletal animation in Metal, SCNKit would be using the GPU to deform the mesh as well. But to do it in Metal you would need to pass skin weights, along with bone matrices for the bind pose and the transformations of the bones as they animate then calculate the new vertex positions based on these. In fact I think you need the inverse of the bind pose matrices. Each mesh vertex is then transformed by a weighted sum of transformations dictated by the skin weights.
I tried it but screwed it up somehow it didn’t deform properly, I don’t know if I’d obtained the wrong matrices from my custom script to grab animation data from blender or a bug in my shader maths or from the weights.
It was probably close, but with all the possible things that I may have got wrong in the process it was difficult to fix so I abandoned it in the end.
Probably easier to stick with SceneKit and let apple take care of the rest or use an existing game engine such as Unity.
Then again if you want a challenge, I’m sure it’s possible, just a little tricky. You could try CPU first to make sure the maths is ok then port it to the GPU to make it faster?
SceneKit do support shaders. And an object that manages the relationship between skeletal animations and the nodes and geometries they animate is SCNSkinner from SceneKit.
Typically, you need to create a skinned model using, for example, Autodesk Maya, save it along with animations that use the skeleton, in a scene file. You load the model from the scene file and pose or animate it in your app, either by using animation objects also loaded from the scene file or by directly manipulating the nodes in the skeleton. That's it.
Watch this 7-parts video about Blender's skeletal system and how to use it in SceneKit.
convenience init(baseGeometry: SCNGeometry?, //character
bones: [SCNNode], //array of bones
boneInverseBindTransforms: [NSValue]?, //ibt of matrix4
boneWeights: SCNGeometrySource, //influence on geometry
boneIndices: SCNGeometrySource //index mapping
)
We are doing a virtual dressing room project and we could map .png image files on body joints. But we need to map 3D clothes to the body and the final out put should be a person(real person not an avatar) wearing a 3D cloth on a live video out put. But we don't know how to do this. Any help is so much appreciated.
Thanks in advance.
Answer for user3588017, its too lengthy but I'll try to explain how to get your project done. First play with XNA with their basic tutorials if you are totally new to 3D gaming. In my project I only focused on bending hands down. For this in you need to create a 3D model in blender and export it to .xna. I used this link as a start. the very beginning Actually this is the most hardest part after this you know how to animate your model using maths. Then you need to map kinect data as (x,y,z) to the parts of your model.
Ex:- map the model rotation to kinect's model rotation. For this I used simple calculations like measuring the depth of the shoulders and calculating the rotated angle and applied it to my cloth model.