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Thread: What is the workflow with Bvh?

  1. #31
    Banned OnlineRender's Avatar
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    Cheers Splinegod for your help the other night , granted it was 2am but i did learn something , infact alot . . quick question ,i keep getting mesh deformation , bad !

    STEP BY STEP

    #Step 1
    Layout :
    goto file :
    Import Mo_CAP setup ,BVH data !
    there are 2 nulls , motion preview and usually HIP / ROOT bone null, select the null called hip or whatever the mocap data is attached to in the timeline

    Step 2 ; on the null hit " P " for properties and goto the geomatry tab and add IK_Booster double click on this and it will activate IK

    Step 3 :
    bring up the dope sheet "small grey tab above keyframe timeline " select all the key frames on the dopesheet and right click on the selected frames to bring up the track menu ,then select delete "all items" from range 1-whatever your end frame is ,
    now delete all motion and key frames from object and leaves you with only the bone structure ,remember to keep frame "0" always .

    Step 4 :

    Now replace the hip null by going to the items tab , then replace , replace with object "your mesh " ie human model

    QUESTION Q & A : goto step 5 if all is correct

    THIS IS WHERE I NEED MORE clearer instruction but i will continue on with rough guide . .


    once you have the model in , goto setup tab then bone edit ,this will take you into the bone edit mode ::::::

    i gather you switch off deformation and align your bones to the mesh ,in bone edit ?

    this is where i get the problem when i align the bones in bone edit mode , on keyframe 0 then come out bone edit mode , when i hit deform , it moves the mesh as if though it was using the original bone setup and moves the mesh to what i have aligned the bones to ie if i move the leg bone in bone edit say for example 3 feet ,then come out of bone edit it moves the 3 ft plus what the original placement was .

    " i think i know the answer but hopefully it will help other people overcome this issue"

    is it because i have not rested the bones ??



    STEP 5 :

    Ok so we have rested all bones in bone edit mode by hitting the R key to rest !
    we come out of bone edit mode and back into the scene .

    Step 6 : again on the same scene file we import the bvh data , again apply IK to the new hip null 2 .

    Step 7 : on the dope sheet select all keyframe and on the right hand side IKB MENU , select motion , motion save " save the motion file "

    Step 8 :

    now go back to the original hip null " the one with your model attached " make sure ik boost is applied on the right hand side next to the dope sheet do the same again except instead of going to motion , motion copy goto motion load ,and load in the motion data txt file ,

    STEP 9 , if everything has gone correctly it will come up with a menu showing that so many motions have been applied , scroll threw the timleine and the model should now move ,




    OK thats a rough a guide that splinegod talked me threw so all credits goto him not me , i was just the guy that nodded my head and tryed to take in everysingle word uber being one of them LOL , but again it was 2am and i was whacked .

    so i wrote this to refresh my memory , its not 100% correct so please edit and amend for future reference

    , now back to the issue of bone edit mode at the start , can we make that step clearer

    cheers

    OR
    Last edited by OnlineRender; 05-03-2009 at 10:53 AM.

  2. #32
    Quote Originally Posted by Megalodon View Post
    I've gotten into the Optitrack > MotionBuilder > Lightwave flow and it's worked flawlessly. I've only done about half a dozen test files, but the only problems I've had are user-error ones. Once you get the workflow down, it's very simple. Of course... getting all of your BVH files from one source (ie. not all over the web) makes it MUCH easier. Having to contend with only one base BVH template allows getting things into LW very straight-forward.
    Well I can imagine with that workflow you won't have much trouble. Motion Builder looks awesome but am a bit scared of Autodesk, probably needlessly. Still can't find the price on the website, something around a thousand?

  3. #33
    Quote Originally Posted by SplineGod View Post
    In a nutshell what I told Aaron was to
    Import the bvh file which creates the bone structure.
    Apply IKB and use that to quickly delete all motions.
    Object replace the main null with his character
    Make the bones fit the new mesh.
    Load bvh file again.
    Apply IKB
    Copy motion from bvh rig to his rig using IKB.
    If the rig matches your object and youve rested all the bones
    there shouldnt be any major deformation issues.
    ...
    Precious little truth in this last statement . Aaron has weight maps in his example.

    Don't want to be too unpleasant, but it's rather depressing. Whether this is all related to a different workflow or selling toots I don't know?.....But must take my hat off to Aaron for posting his work which gave invaluable clues to solving this.

    The workflow is simply as follows: (No copy and paste crap)

    0. Adjust mesh to bvh size in layout to get an idea of BVH scale size.

    1. Load mesh into modeler and the BVH (Mocap skelegons). Fit mesh to bones for exact position and size.

    2.Open layout and import BVH data, swap out null for mesh.

    3. Weight maps


    The following observations the royal we believe to be true:

    1. Putting the bones at rest is irrelevant (this has been taken care of in Modeler -no.1 above).

    2. BVH skeleton may not match the mesh that well or at all, this is a given.

    3 Whether the mesh can be altered without breakinig the montion in BVHacker is unknown.

    4, Damaged or different format BVH files is not an issue as this is obvious when they are imported.

    5. Weight maps in some form are essential unless in the unlikely case of a perfect match up with mesh

    6. Help with tips etc. on weightmaps would be useful at this stage but don't expect it to happen.

  4. #34
    Quote Originally Posted by OnlineRender View Post

    ...
    once you have the model in , goto setup tab then bone edit ,this will take you into the bone edit mode ::::::

    i gather you switch off deformation and align your bones to the mesh ,in bone edit ?

    this is where i get the problem when i align the bones in bone edit mode , on keyframe 0 then come out bone edit mode , when i hit deform , it moves the mesh as if though it was using the original bone setup and moves the mesh to what i have aligned the bones to ie if i move the leg bone in bone edit say for example 3 feet ,then come out of bone edit it moves the 3 ft plus what the original placement was .

    " i think i know the answer but hopefully it will help other people overcome this issue"

    is it because i have not rested the bones ??
    .... now back to the issue of bone edit mode at the start , can we make that step clearer

    cheers

    OR
    Hi there OnlineRender,

    Well the Scots didn't invent insurance for nothing(?) Glad to see someone else has a real interest in sorting this out!

    I stand by what I say above. But to be honest I do have a slight doubt about resting bones and the bone edit stuff, but really think its nonsense.

    I am quite happy to be proved wrong, but think we need to deal in empirical knowledge here.

  5. #35
    Empirical attachments:
    Attached Files Attached Files

  6. #36
    Banned OnlineRender's Avatar
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    Weight Maps are easy ! but Splinegod mentioned a weight map blur plugin , you select the top half & buttom then use the plugin to blend the maps together ,
    to create weight maps >go into modeler ,select your polyz that you want to weight then goto to the weight map at the buttom right ,

    so effectivly ur saying go into modeler and set the bones there ,
    then back into layout import the motion again

  7. #37
    Quote Originally Posted by OnlineRender View Post
    Weight Maps are easy ! but Splinegod mentioned a weight map blur plugin , you select the top half & buttom then use the plugin to blend the maps together ,
    to create weight maps >go into modeler ,select your polyz that you want to weight then goto to the weight map at the buttom right ,
    I used weight maps in the last one posted. You can see from the animation posted as well that everything is basically fine except right under the shoulders, so this has to be refined.

    There is no big deal. It's just unless the mo-cap skeleton fits the mesh EXACTLY, there is no way to make it work without the weight maps. It seemed to me that PEOPLE were suggesting otherwise and it wastes a lot of time and effort trying to do something that is impossible.


    Quote Originally Posted by OnlineRender View Post
    so effectivly ur saying go into modeler and set the bones there ,
    then back into layout import the motion again
    I'm saying there are only 3 steps ( the first 0 step is to determine scale and not essential), and when you exclude the weight map part there are only 2 steps (you can forget the IKB part).

    1. Load mesh into modeler and the BVH (Mocap skelegons). Fit mesh to bones for exact position and size.

    2.Open layout and import BVH data (the skeleton with the motion appears) swap out null for mesh (replace with object). (The object, mesh will be in the exact right place as it was set to those coordinates in Modeler)

    That's it -no Mumbo Jumbo.
    Last edited by Glendalough; 05-03-2009 at 03:31 PM.

  8. #38
    Super Member SplineGod's Avatar
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    Quote Originally Posted by Glendalough View Post

    There is no big deal. It's just unless the mo-cap skeleton fits the mesh EXACTLY, there is no way to make it work without the weight maps. It seemed to me that PEOPLE were suggesting otherwise and it wastes a lot of time and effort trying to do something that is impossible.
    Im going to disagree. Regardless if you use weight maps or not the bones have to fit as exactly as possible. If they dont the mesh will rotate from the wrong places etc and no amount of weight maps or no weight maps will fix that other then to make sure the bones are in the right places.

    A big part of the reason I use IKBoost which I demonstrated to Onlinerender the other night was that once I have the Mocap imported I can manipulate and use the mocap in ways that are just not possible in LW without IKBoost.

  9. #39
    Banned OnlineRender's Avatar
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    how do you size bones in BONE EDIT mode without stretching the mesh , is it bone move tip ?im sure ive seen a video on it before

  10. #40
    Super Member SplineGod's Avatar
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    You can adjust the rest length even after the bones have been rested.
    You can use joint edit or tip move as well. Make sure to rerest your bones.

  11. #41
    Banned OnlineRender's Avatar
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    still get the same error , when i import bvh and replace null with mesh , i then move bones around into correct position using bone edit , i rest all the bones , when i bring back the bvh data and apply ik and copy motion it reverts back to original stance , ive tried to save and import the original pose on keyframe 0 , but again it still acts funky ,

    any ideas ?

  12. #42
    Super Member SplineGod's Avatar
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    The first part is to get the bones lined up so you have a rest pose so that the mesh will move ok with the bones. Once you reimport the motion data that rest pose will be lost.
    Keep in mind that you can copy and paste the motion data so that you skip the frame with your rest ppse.

  13. #43
    Banned OnlineRender's Avatar
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    BVH QUICK TEST RENDER : www.youtube.com/onlinerender

    i notice the keyframe jump , i need to animate arms manualy but it looks ok

  14. #44
    Super Member SplineGod's Avatar
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    Nice! Glad to see you got it working.

  15. #45
    Banned OnlineRender's Avatar
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    ye it was a nightmare at first , but now i can i get bvh data into LW within minutes , again cheers for help , much appricated , enjoy your long holiday and have a safe trip i might make a video tut on this area , if you dont mind ?

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