Specifying Per-Material Fields Using Blueprint?

[xjrc]

I'd like to use Blueprint to describe a mesh that has multiple materials in a single zone, where each material has its own value for a particular field (e.g. density). Does Blueprint have any mechanism for describing such a field? If not, what would be the best way to utilize Blueprint's existing schema to describe such a field? Thanks in advance!

[cyrush]

these would simply be mcarrays named in a way that would allow us to understand they are density for each material

for example, if I have 3 materials, we could have an mcarray:

per_material_density:
{
den_mat_1: vals
den_mat_2: vals
den_mat_3: vals
}

and associated:

vol_fracs:
{
mat_1_vf:
mat_2_vf:
mat_3_vf:
}

of course in the future, we need to support sparse representations -- and would share indices across these type of mcarray reps

beyond this we can think about grouping via a hierarchy, having a special treatment for material fields

{
volume_fractions: { }
fields: {}
}

[xjrc]

Storing per-material fields as an mcarray seems very sensible to me, and I like the idea of interpreting materials as a special type of field in Blueprint.

Given this information, I'd imagine that a Blueprint mesh with per-material fields would look like this:

mesh: {
  domain0: {
    /* coordsets, topologies */
    fields: {
      /* material is a reserved field name */
      material: {
        type: "scalar",
        association: "element",
        topology: "topology0",
        values: {
          material0: [ /* volume fractions for material 0 */ ],
          ...
          materialN: [ /* volume fractions for material N */ ],
        }
      },
      field0: {
        type: "scalar",
        association: "element",
        topology: "topology0",
        values: {
          material0: [ /* per-material field values for material 0 */ ],
          ...
          materialN: [ /* per-material field values for material N */ ],
        }
      },
      /* other fields */
    }
  },
  /* other domains */
}

Does this interpretation of Blueprint with materials seem correct, or is there something I'm missing? Thanks again for your help and I'm sorry if I'm missing anything obvious!

[cyrush]

yes -- close to what I am thinking, lets chat in person to discuss using high bandwidth.

[xjrc]

Based on our discussion, it seems like preliminary support for materials and per-material fields will look something like the following:

mesh: {
  domain0: {
    /* coordsets, topologies */
    materials: {
      association: "element",
      topology: "topology0",
      volume_fractions: {
        material0: [ /* volume fractions for material 0 */ ],
        ...
        materialN: [ /* volume fractions for material N */ ],
      }
    },
    fields: {
      field0: {
        type: "scalar",
        association: "element",
        topology: "topology0",
        values: {
          material0: [ /* per-material field values for material 0 */ ],
          ...
          materialN: [ /* per-material field values for material N */ ],
        }
      },
      /* other fields */
    }
  },
  /* other domains */
}

I'm going to close this issue for now, but we can reopen it when we refine the material and per-material field specifications in Blueprint.

[cyrush]

that sounds good, I would just add that under "materials" we will want to have a name -- to support the possibility of multiple material volume fraction sets

[xjrc]

Just a few quick examples for reference:

Multi-Material, Single-Component Fields

{
  "coordsets": 
  {
    "domain0": 
    {
      "type": "explicit",
      "values": 
      {
        "x": [0.0, 0.333333343267441, 0.666666686534882, 1.0, 0.0, 0.333333343267441, 0.666666686534882, 1.0, 0.0, 0.333333343267441, 0.666666686534882, 1.0, 0.0, 0.333333343267441, 0.666666686534882, 1.0],
        "y": [0.0, 0.0, 0.0, 0.0, 0.333333343267441, 0.333333343267441, 0.333333343267441, 0.333333343267441, 0.666666686534882, 0.666666686534882, 0.666666686534882, 0.666666686534882, 1.0, 1.0, 1.0, 1.0]
      }
    }
  },
  "topologies": 
  {
    "domain0": 
    {
      "type": "unstructured",
      "coordset": "domain0",
      "elements": 
      {
        "shape": "quad",
        "connectivity": [0, 1, 4, 5, 1, 2, 5, 6, 2, 3, 6, 7, 4, 5, 8, 9, 5, 6, 9, 10, 6, 7, 10, 11, 8, 9, 12, 13, 9, 10, 13, 14, 10, 11, 14, 15]
      }
    }
  },
  "materials": 
  {
    "LL": 
    {
      "type": "scalar",
      "association": "element",
      "topology": "domain0",
      "values": [1.0, 0.5, 0.0, 0.5, 0.25, 0.0, 0.0, 0.0, 0.0]
    },
    "LR": 
    {
      "type": "scalar",
      "association": "element",
      "topology": "domain0",
      "values": [0.0, 0.5, 1.0, 0.0, 0.25, 0.5, 0.0, 0.0, 0.0]
    },
    "UL": 
    {
      "type": "scalar",
      "association": "element",
      "topology": "domain0",
      "values": [0.0, 0.0, 0.0, 0.5, 0.25, 0.0, 1.0, 0.5, 0.0]
    },
    "UR": 
    {
      "type": "scalar",
      "association": "element",
      "topology": "domain0",
      "values": [0.0, 0.0, 0.0, 0.0, 0.25, 0.5, 0.0, 0.5, 1.0]
    }
  },
  "fields": 
  {
    "temp": 
    {
      "type": "scalar",
      "association": "element",
      "topology": "domain0",
      "values": 
      {
        "LL": [15.0, 15.0, 0.0, 15.0, 15.0, 0.0, 0.0, 0.0, 0.0],
        "LR": [0.0, 5.0, 5.0, 0.0, 5.0, 5.0, 0.0, 0.0, 0.0],
        "UL": [-0.0, -0.0, -0.0, -5.0, -5.0, -0.0, -5.0, -5.0, -0.0],
        "UR": [-0.0, -0.0, -0.0, -0.0, -15.0, -15.0, -0.0, -15.0, -15.0]
      }
    }
  }
}

Multi-Material, Multi-Component Fields

{
  "coordsets": 
  {
    "domain0": 
    {
      "type": "explicit",
      "values": 
      {
        "x": [0.0, 0.333333343267441, 0.666666686534882, 1.0, 0.0, 0.333333343267441, 0.666666686534882, 1.0, 0.0, 0.333333343267441, 0.666666686534882, 1.0, 0.0, 0.333333343267441, 0.666666686534882, 1.0],
        "y": [0.0, 0.0, 0.0, 0.0, 0.333333343267441, 0.333333343267441, 0.333333343267441, 0.333333343267441, 0.666666686534882, 0.666666686534882, 0.666666686534882, 0.666666686534882, 1.0, 1.0, 1.0, 1.0]
      }
    }
  },
  "topologies": 
  {
    "domain0": 
    {
      "type": "unstructured",
      "coordset": "domain0",
      "elements": 
      {
        "shape": "quad",
        "connectivity": [0, 1, 4, 5, 1, 2, 5, 6, 2, 3, 6, 7, 4, 5, 8, 9, 5, 6, 9, 10, 6, 7, 10, 11, 8, 9, 12, 13, 9, 10, 13, 14, 10, 11, 14, 15]
      }
    }
  },
  "materials": 
  {
    "L": 
    {
      "type": "scalar",
      "association": "element",
      "topology": "domain0",
      "values": [0.0, 0.5, 1.0, 0.0, 0.5, 1.0, 0.0, 0.5, 1.0]
    },
    "R": 
    {
      "type": "scalar",
      "association": "element",
      "topology": "domain0",
      "values": [1.0, 0.5, 0.0, 1.0, 0.5, 0.0, 1.0, 0.5, 0.0]
    }
  },
  "fields": 
  {
    "velo": 
    {
      "type": "vector",
      "association": "element",
      "topology": "domain0",
      "values": 
      {
        "L": 
        {
          "x": [2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0],
          "y": [-2.0, -2.0, -2.0, -2.0, -2.0, -2.0, -2.0, -2.0, -2.0]
        },
        "R": 
        {
          "x": [4.0, 4.0, 4.0, 4.0, 4.0, 4.0, 4.0, 4.0, 4.0],
          "y": [-4.0, -4.0, -4.0, -4.0, -4.0, -4.0, -4.0, -4.0, -4.0]
        }
      }
    }
  }
}