Modeling a wheel...



  • I need to model a skate truck with wheels. For the most part not really that hard to do, except for the wheels. Should they be free from or part of the axle? In a still render, that's not really an issue since the wheels don't move. But if the skates are used in an animation do the wheels and axle spin as a unit or individually?



  • @eclark1849 if memory serves, roller skate trucks and wheels use the same pattern as skate boards, which have fixed (though steerable) axles and ball races within the wheels. The same type, though larger wheels are also used on inline skates. So, wheels rotate, axles don't.



  • @anomalaus said in Modeling a wheel...:

    @eclark1849 if memory serves, roller skate trucks and wheels use the same pattern as skate boards, which have fixed (though steerable) axles and ball races within the wheels. The same type, though larger wheels are also used on inline skates. So, wheels rotate, axles don't.

    Ooh, good point. Been awhile since I've been on a pair of skates. Might as well pull mine out and study them closer instead of the pics I've been looking at online.



  • This will probably be a freebie if any one is actually interested. The skateboard, not Andy. At the moment though it has no mat zones.

    0_1545516113267_skateboard.png



  • @eclark1849 Oh, that's looking nice Earl.



  • @eclark1849 When I made a skateboard awhile back, I modeled every piece of it separately, so that grouping and materials would be easy. I haven't rigged it yet, but there is a picture of it in the Superfly thread. I can repost it if you want to see it...



  • @rokketman No need, but thanks. I have no intention of rigging this skateboard. It is purely for static renders.



  • @eclark1849 Okay. I didn't rig mine either. It's a bit daunting.



  • @rokketman & @eclark1849 you don't actually need to rig wheels or mechanical joints as such except setting their origins and endpoints. Whether the wheels are props or actual bodyPart actors, none of the tedious and fiddly joint parameters are required at all. There are no smoothing zones or tapers or anything that connects a wheel to it's parent axle except the parenting. The skate(board) truck axles also only rotate about one axis, angled towards the board's centre, which both steers, and keeps the wheels flat on the ground as the board tilts laterally. Very economical to rig.



  • @anomalaus Except for importing into Poser, the wheels are not attached to the axles.



  • Been awhile since I've messed with Blender, and texturing has never been my strongsuit. So naturally, I've forgotten how to apply a UV map. :)

    0_1545615637113_1078c797-d1be-4dac-80f0-021dfcad4533-image.png



  • @eclark1849 I was working in Blender today making a dress, which I decided to add a lace detail to the skirt. Got ity into poser and couldn't understand why when I applied a nice lace texture to the lace it wouldn't render at all, then I remembered I hadn't UV unwrapped it in Blender (Slapped head after wasting half an hour!)



  • @amethystpendant I did that, though. Usually, I can see the texture. But this time, I've forgotten something.



  • @amethystpendant Ohhhh, I remember those days.



  • I would build the skate board as a (how I call it) "Prop Figure"

    This means, build all the various parts (plank, axles, wheels) as individual props and texture them (much easier for the single parts than for a full-fledged figure).

    Save each part as a wavefront.obj.
    If the .obj items are already in the correct place in 3D space relative to the other parts, even the better because it spares you the trouble with offsets.

    You can circumvent this partially (if your modeling program can't do this already) if you load all .obj files, assemble them where they need to be, then use Poser's Grouping Editor:

    Select each single .obj prop, create a new group (I use ALL as a name), then click "Add all" and then spawn a new prop for each item.

    Delete the previous .obj, all of them to avoid clutter because next comes the step of parenting, and one of Poser's notorious small windows to select the items to be saved to the library, and it's easier to check/unckeck the right items.

    After the superflous .obj are gone,

    • parent the parts of your "soon-to-be" Prop Figure, e.g. pivots to plank, axles to pivots, wheels to axles.
    • then save the whole conglomerate as a temp prop to the props library (make sure to select the correct props - that's why I advised to delete all the superflous .obj before).

    SAVE THE SCENE NOW by a .temp name, just to have a fall back in case something goes wrong!

    Now open a new scene and reload that temp prop to check whether everything loads in the correct place.

    Next, let's "rig" this:

    Go to EVERY SINGLE PROP in your model, and LOCK it so it disallows any xyz movements, or rotations, or scaling which isn't possible, mechanically!
    DO NOT USE the Poser Menu "Lock..." because it can be easily overridden.
    Instead, you have to call every single move/rotate/scale dial, check "Force Limits" and set the "Min/Max" values to what you want to allow!

    (If you have my SASHA-16, there's a Python script "Lock/Unlock Prop" which will be of great help here)

    What's the advantage of a "Prop Figure"

    Well, you now have a group of props which can only move/rotate in the directions that you explicitly allowed during setup.
    E.g.:
    Wheels can't rotate along their z axis, axles (and wheels) will only rotate/yaw along the limits you imposed, and you can't dislocate them accidentally, except if you explicitly allow it per the settings.

    The other advantage of course is that it's not a clumsy and memory eating figure, but they are all still simple props.
    So no more worry about "hip" offsets, or grabbing the "figure circle":
    Just grab the board plank and move it into place!

    And just in case you want to simulate a detached wheel or whatever:
    Simply unparent the detached wheel and move it to where it should land (Murphy's Law says: "Right down the next sewer opening :D )

    This "Prop Figure" is in fact my own invention, and I used it on vehicles, tanks, weapons with great results!
    If you want more details about how to build a "Figure Prop", just ask!

    B.t.w, MERRY CHRISTMAS TO ALL OF YOU!

    Karina


  • Poser Ambassadors

    @karina If your modelling in Blender, there is basically no reason to use Poser in the process.

    Grouping in Poser is one of the best ways I know of, of destroying the winding order on export.



  • Hello shvrdavid,

    why should I export anything?

    What I do is model all the single parts somewhere, then IMPORT the UV'ed .obj files and convert each object to a Poser prop.

    Then I parent all props to the master prop (the board plank in this case) and "lock" everything in place by the method described above.

    No need for exporting anything at all, and Poser will happily handle the new props created by itself and by it's own rules.

    I never had problems, even when kitbashing and cannibalizing other props or even figures.

    See my AK-74 for an example:
    0_1545850831600_AK-74 promo 1.jpg
    These are all props, and the whole thing was made by kitbashing in Poser only.

    Cheers!

    Karina


  • Poser Ambassadors

    @karina
    @shvrdavid

    Hey, hello you 2. Both are correct because you two have a completely different workflow.

    Karina uses separate item props. They are never connected to anything and the grouping issue of splitting obj files and creating double verts does not apply in this case. If you model and assemble using individual items, => clear case.

    Best regards all.


  • Poser Ambassadors

    @karina

    I have done props the way you mentioned and run into a few issues.
    Oddly, it doesn't do it every time, or always do the same things.

    I have had the group editor trash winding orders simply using spawn prop.
    Even after checking that nothing was odd in the original, I could not figure out why it did that.
    Doing it again, oddly it worked. So, dunno what happened.

    I have also saved kit bashed props, that worked, and ones that had oddities that showed up in renders.
    I can see some of what I ran into, in your render.
    It is hard to judge if it is a similar issue without seeing the wire frame and the winding order in the prop file.

    Basically I just started doing everything in the modeler, which eliminates the oddities that can crop up when using multiple programs to make something. My prop files usually call single obj files saved from the modeler that are not embedded into the prop save file. I have seen differences in the original versus the embedded meshes as well. Any movement I want to do, is done with morphs more often than not as well. I guess that is a carry over from using blend shapes, etc, in other apps.

    Like Vilters said, different work flows to get to the end result.


  • Poser Ambassadors

    Like Scott, I always do vertex group work externally just to avoid issues.
    And to be on the safe side => Never export an obj from Poser till a permanent fix is available for the vertex group splitting/double vertex at welds issues.