Pose User-Defined Surfaces/Entities

[VigneshYork]

Hi,

I have two questions regarding the pose tool:

1. In the example stated at the start of this thread regarding drawing a patch on the surface of the skin and posing the patch with the model: would the patch also deform similar to the skin? Is the FEM applied to the patch also?

2. I am getting the following issue (figure attached). The bone and muscle are split. I am not sure how to fix this

Thanks

[bryn]

1. the FEM model is used to compute a deformation in the entire body. The deformation is applied to all surface entities (and patches defined on those surfaces). A patch on a triangle mesh is actually just a subset of that surface (a list of triangles).

2. I have never observed this issue. Did you use the move tool before/after/while using the poser? Can you explain the steps to reproduce this issue?

[VigneshYork]

Hi Bryn,

Thanks for your clarifications.

1. If I extrdue the patch to make a cloth or band around the leg. Would that deform too?
2. The way to reproduce the issue is to move the model to a different location and then pose it.

Thanks

[bryn]

ok,

1. if the extrusion layer is thin enough it may deform reasonably. Deformation of surfaces outside the body is based on nearest neighbor extrapolation. You could also extrude the patch after posing.
2. Thanks, I will create a bug report so we can address it. I guess a workaround is to move after posing. Sorry for the inconvenience.

[ofli]

@VigneshYork Which Sim4Life version are you using?

[VigneshYork]

Hi, I am using version 7.0.1.8169

[ofli]

Please download and install the latest version of Sim4Life (V7.2.4) with which you should not experience this issue.

[VigneshYork]

@bryn I have a follow up question to this. If I draw a cylinder over the bone and provide it properties of muscle, do I need to subtract the bone from the cylinder?

For example: When I observe the voxels in the ViP model for muscle only (without the presence of bone or anything), there is a hole where the bone is suppoed to be (which makes sense) (Figure attached).

Do I need to do the same with a custom cylinder i.e subtract the bone from the cylinder? The voxels with the cylinder with bone shows the presence of the bone (Figure attached) but not for all cases.

Thanks

[bryn]

you can, but it is easier to simply use the priorities. if you set the cylinder to a higher priority than bone it will be voxeled over the bone. a voxel can only represent one material, so what ever has higher priority wins.

[VigneshYork]

Thank you. What happens when all elements are given the same priority and you do not subtract the bone from the muscle? What would a voxel at the location of the bone present?

@ofli : Thank you. Installing the new version removed the error.

[bryn]

@VigneshYork it will seem like a random ordering. If I remember correctly, the ordering will depend on the unique identifier of the entities (entity.Id). If you need to ensure a specific ordering you have to use the priorities (OR do the boolean subtraction). The priority approach is very robust though.

[VigneshYork]

Thank you

[VigneshYork]

@ofli : sorry but the error happened again with sim4life 7.2. Once I moved the model and tried to pose it, the bones and rest of the model separated

[VigneshYork]

Hi Bryn,

I would like to ask a question regarding posing. My aim is to detect the variation in bone position from the skin in different poses (hypothesis being: as the soft tissues deform, the bone wont always be at the same position wrt the skin). I currently have 8 antennas placed around the skin which are supposed to mimic wearable antennas and I would like to move these antennas along with the pose.

But if I link these antennas to the bone using "link-parent tool", the bone is always at the same location wrt to the bone irrespective of the pose. But I cannot link the antennas wrt to the skin as the antennas dont move with the pose.

1. How can I do this? I would like the antennas which are placed around the skin to similar to the skin rather than the bone?
2. Based on the first video in this chain, triangular meshes can be posed similar to the body. If I convert the antennas to meshes and then pose it, will I be getting the same issue i.e the bone is always at the same location wrt to the antennas?

Thanks