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johnm

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About johnm

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    john
  1. H16 lags

    helpful little tip for people who hate waiting for the tooltip info that pops up when you hover over a shelf tool, or parameter, etc.... if you hold the CTRL key while you hover, the tooltip pops up instantly.
  2. Muscle controls

    custom geo muscles are already possible: http://forums.odforce.net/topic/29052-fem-muscle-external-geo-physical-simulation/?do=findComment&comment=164817 and as always, please feel free to rfe. -j
  3. Muscle controls

    The future plan is to fix this. It is indeed a bug. The 16.0 release version had a line of wrangle code "optimized" away. The handles are capable of rotating the orientation of the corresponding muscle area. Not so obvious with a muscle made of perfect spheres, but if non-uniform scaling is applied in the Geometry Tab >Muscle Radius, you can make flat muscle profiles, and twist the face of the muscle geometry with the handle orientation. -Also applicable to deforming muscles made of custom geometry. -john
  4. there are currently a couple of options you have for using your custom models as muscles. but first, it's important to note that rather than pinning points explicitly, we've decided to deploy control over the muscles with the notion of using a "rig" instead. In Houdini16, Muscle Rigs and Muscle Pins can be used to "capture" regions of your muscle geometry and parent them to objects and bones in your character rig. This provides you with a quick and easy set of tools in the same context as the rest of your character. The rig remains agnostic to the geometry making up your muscle. This means you're able to model and remodel the muscle geometry without invalidating any of your constraints. On the other end, your Muscle Rigs and Muscle Pins will seep constraint data into your custom modeled muscle as it's converted to a tetmesh so that the FEM solver can manipulate your geometry properly. The two ways you can bring external models into the muscle system are: The Muscle shelf tool (riggedmuscle object node) creates a muscle with built-in geometry and a single, self-contained muscle rig. This is adequate for most "bicep-style" muscles. On the Geometry tab, the Build parameter can be switched to use External Geometry. Once you've toggled that, you can specify the path to the geometry you want to use as your muscle. Keep in mind that it will be captured and deformed by the single built-in rig. The second way is to use a FrankenMuscle. FrankeMuscles allow you to mix together any number of geometry sources with any number of Muscle Rigs and Muscle Pins to create a new custom muscle creation to suit your needs. Here you can use multiple muscle rigs to attach your muscle to your character rig. And because the system has this layer of separation between your muscle geometry and the solver, you can add, remove, or change your muscle rigging if you're not getting the desired results right away. -it's also worth noting that the muscle rigs have built-in variable jiggle and "fake" volume preservation for additional artistic control. This means your custom models can instantly have access to those features as well as soon as you string a muscle rig through them. -john
  5. hi Hsuan, It's not clear exactly what you're attempting to do but here are a couple of suggestions that might help.... Guide curves need only a guideorigin (primitive) attribute to be used in the Fur Sop. The guideorigin attribute is the point origin of the root of the hair in its static rest position. An easy way to assign this is to use the RestSop to assign a rest position to all the points in your guides (from static non-deforming guides onto your animated guides), and then use an AttribPrmote Sop to promote the "rest" attribute, a point attribute, to a primitive attribute using "First Match". Rename "rest" to "guideorigin" while you're at it. The guideorigin is used in measuring the distance to each hair root to determine if it should be influenced by that guide curve. The GuideRadius parameter on the Fur Sop works in conjunction with this attribute. In your test scene, the guideorigin attribute was not being defined. The AttribCreate sop in your foreach was bypassed. If you enable it, your error goes away. Secondly, your guide curves were some distance from your fur skin geometry. This forces you to have a huge guide radius before you start seeing any effect from the guide curves on the fur. (Values greater than 13 started showing some effect). Once again, not sure what you were attempting to do here. I thought maybe you were trying to grow fur on the sphere geometry, but you didn't mention that in your first post. Incidentally, that wouldn't work either since your sphere was a Primitive type. You'll need to make it polygonal for the fur to work. hope that helps -j
  6. alembic and motion blur

    thought I'd share what I found... First of all, timeblending the geo sampled at integer frame values (lerping translated, for all you youngsters) is fine and all, but I was looking to tap into the sub-sampled geo data. Secondly, point velocity doesn't apply in this situation as we're dealing with deformation blur. My problem was my understanding of what I'd get from Maya's Frame Relative Sampling. The attached rendered pics show a camera shutter angle ramping from 0 to 1.0, with mantra's Geo Time Samples set to 5. The Maya alembic export settings were: -Evaluate Every 1.0 frames (ie integer frame samples) -Evaluate Every 0.1 frames (10 samples per frame) -Evaluate Every 1.0, with Frame Relative Sampling Low=0.0 and High=0.5 and the timeblend version is for comparison.
  7. How does one properly export deforming geometry from maya and import it into houdini in such a way that deformation motion blur works correctly with a 0.5 shutter interval? Maya's alembic export settings: step size = 1, and FrameRelativeSample = 0.0 and 0.5 houdini is set up with camera shutter=0.5 geo_motionsamples=2 I'm getting intermittent frames with no motion blur at all, and, motion blur is as though shutter=1.0. I know I can work around the issue by lerping the geometry sampled at the integer frame values, but I was hoping I wouldn't have to.
  8. Simple attempt to get animation and DOPs to work

    the key thing is to set the RBDSolver to use Point Velocity to compute collisions instead of Volume velocity (or nothing)... If you look at the attached file and display the collision volume in the AutoDop network, in wireframe, you'll notice that box_B slides away as you describe. From what I can tell, the volume representation of the collision geometry is behaving almost like a tractor tread and propelling the box along in the direction opposite to its rotation. Also, increasing the Rotational Stiffness had an impact on how much box_A was able to roll. -j ...attached file this time... rotating_box.hipnc
  9. Bones and DOPS

    you might be able to get somewhere by creating a "stick figure" version of your character and using a WireSolver to do your sim.
  10. have you tried the 'pointavg' expression? depending on where & how you want to evaluate it, the X average would be: pointavg("../scatter1", "P", 0) the Y average: pointavg("../scatter1", "P", 1) and Z: pointavg("../scatter1", "P", 2)
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