Nulamir
commented
2 years ago Hi,
IMU sensors generate quaternions and only rotation information, not position information. Autodesk Motion builder wait for euler angle and mdT (position of node)
Wee need to convert this data
Facts:
- Sensor initial state is start from lying on the table chip Z axis look in to roof. X and Y lying on the table. But on the motionbuilder model. Skeleton is faced to you. Z axis look on you.
2 Sensor physical implementation (crafted hard device) a unified (they are all likes each on enover), But on you body you need to hang sensor on stomach legs head vertically, and in left side of body sensor hanged one method on right side another
3 there is a little deviation then you hang sensors 10-15 degrees from strightly vertical or horizontal position
All calculation made in ordeviceskeleton_hardware.cxx ORDeviceSkeletonHardware::FetchDataPacket(FBTime& pTime)
To get 1,2 Facts you need to remix and redirect axes of quaternion.
cQuaternion.mValue[1] = mSkDataBuffer.mChannel[i].iR[0][0] tempx + mSkDataBuffer.mChannel[i].iR[0][1] tempy + mSkDataBuffer.mChannel[i].iR[0][2] tempz; // -tempz cQuaternion.mValue[2] = mSkDataBuffer.mChannel[i].iR[1][0] tempx + mSkDataBuffer.mChannel[i].iR[1][1] tempy + mSkDataBuffer.mChannel[i].iR[1][2] tempz;//-tempx; cQuaternion.mValue[3] = mSkDataBuffer.mChannel[i].iR[2][0] tempx + mSkDataBuffer.mChannel[i].iR[2][1] tempy + mSkDataBuffer.mChannel[i].iR[2][2] * tempz;//tempy;
Data for how to remix axes stored in ordeviceskeleton_hardware .h void SetupBuffer()
in example of left foot^
mChannel[3].iR[0][0] = -1; mChannel[3].iR[0][1] = 0; mChannel[3].iR[0][2] = 0; x axis reversed mChannel[3].iR[1][0] = 0; mChannel[3].iR[1][1] = 0; mChannel[3].iR[1][2] = 1; y,z a swapped mChannel[3].iR[2][0] = 0; mChannel[3].iR[2][1] = 1; mChannel[3].iR[2][2] = 0; y,z a swapped
Now you may hang your sensor on you comfort
To get 3 Fact you need to multiply correction quaternion on sensor quaternion
multiplyQuaternion(resultQuaternion, correctionQuaternion, cQuaternion);
Now we get Euler angels
getEulerFromQuaternion(cRotationOfNode, resultQuaternion, zyx);
Code below get transformation data mT (position of node) from rotation of bones. code use sceleton data. length of bones they initial position.
mSkDataBuffer.mChannel[i].mR[0] = cRotationOfNode.mValue[0];// +correctionVector.mValue[0]; mSkDataBuffer.mChannel[i].mR[1] = cRotationOfNode.mValue[1];// -correctionVector.mValue[1]; mSkDataBuffer.mChannel[i].mR[2] = cRotationOfNode.mValue[2];// -correctionVector.mValue[2];
// Copy data to head SkeletonNodeInfo* lIter; lIter = &mChannel[i]; // значение ноды //memcpy(lIter->mT, mSkDataBuffer.mChannel[i].mT, sizeof(lIter->mT)); memcpy(lIter->mR, mSkDataBuffer.mChannel[i].mR, sizeof(lIter->mR));
if (true) { FBMatrix lTransformation, lChannelTransformation, gTransformatilon; // prepare martix to rotation
//FBQuaternionToMatrix(lTransformation, cQuaternion);
FBRotationToMatrix(lTransformation, mSkDataBuffer.mChannel[i].mR);
for (int j = 0; j < mSkDataBuffer.ChildrensCount; j++) { int children = mSkDataBuffer.mChannel[i].children[j]; if (children != -1) // 0 = hips {
memcpy(&lChannelTransformation[0], mSkDataBuffer.mChannel[children].mdT, sizeof(mSkDataBuffer.mChannel[children].mT)); //дельту от родителя //берем FBMatrixMult(lChannelTransformation, lTransformation, lChannelTransformation);// поворачиваем на кватернион родителя
memcpy(&gTransformatilon[0], mSkDataBuffer.mChannel[i].mT, sizeof(mSkDataBuffer.mChannel[i].mT)); //достаем родительскую ноду текущую
lChannelTransformation = lChannelTransformation + gTransformatilon; //вернуть нужно в глобальных координатах, то есть сложить с родительской нодой
memcpy(&mSkDataBuffer.mChannel[children].mT, &lChannelTransformation[0], sizeof(mSkDataBuffer.mChannel[children].mT)); // here is updating transfers
lIter = &mChannel[children];
memcpy(lIter->mT, mSkDataBuffer.mChannel[children].mT, sizeof(lIter->mT));// значение ноды
}
} }
чт, 30 дек. 2021 г. в 05:38, BestPolarBear @.***>:
Hello, how do you convert the sensor coordinate system to the model node coordinate system?I'm doing something similar to you, but there are some problems with coordinate system conversion.
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You are receiving this because you are subscribed to this thread.Message ID: @.***>
Hello, how do you convert the sensor coordinate system to the model node coordinate system?I'm doing something similar to you, but there are some problems with coordinate system conversion.