# Struggling to plot geometry with mix\_materials
**URL:** https://openmc.discourse.group/t/struggling-to-plot-geometry-with-mix-materials/4798
**Category:** User Support
**Created:** [September 15, 2024, 5:07am UTC](https://openmc.discourse.group/t/struggling-to-plot-geometry-with-mix-materials/4798 "2024-09-15T05:07:40Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@danii](https://openmc.discourse.group/u/danii)
#### Post date: [September 15, 2024, 5:07am UTC](https://openmc.discourse.group/t/struggling-to-plot-geometry-with-mix-materials/4798/1 "2024-09-15T05:07:40Z")
Hi, I encountered this error while trying to plot universe with mix\_materials involved in it. Here the code
```auto
core_1_uni.plot(basis = 'xy', origin = [0, 0, 0])
```
the error
```auto
No macroscopic data or nuclides specified on material 9 -------------------------------------------------------------------------- MPI_ABORT was invoked on rank 0 in communicator MPI_COMM_WORLD with errorcode -1. NOTE: invoking MPI_ABORT causes Open MPI to kill all MPI processes. You may or may not see output from other processes, depending on exactly when Open MPI kills them. --------------------------------------------------------------------------
```
material 9:
```auto
mix_fast = openmc.Material(name = 'Homogenised Fast Material')
mix_fast.mix_materials([UO2, PuO2, SUS, sodium], [0.56, 0.14, 0.1, 0.2], 'wo')
materials.append(mix_fast)
```
how can i resolve this error? thank you 🙏. also very sorry for my bad english
---
### Author:  [@wahidluthfi](https://openmc.discourse.group/u/wahidluthfi)
#### Post date: [September 16, 2024, 12:16am UTC](https://openmc.discourse.group/t/struggling-to-plot-geometry-with-mix-materials/4798/2 "2024-09-16T00:16:16Z")
Hi Rahmadani, welcome back to the community.
I think the problem came from your mixed materials input, which makes the material has no isotopes in its composition and failed to plot.
Instead of initializing mix\_fast as and openmc.Material and add the mix\_materials properties in it, you can declare the mix\_fast directly as a mix material. then the openmc will declare each isotope composition.
this is what it looks like when you use your input, the mix\_fast will be empty
but, if you declare your mix\_fast as an openmc.Material.mix\_materials (directly), then it will look like this and the composition will be added to the material
here is the modified input script, you can add a name or if you forgot, then by default, it will use the mix material fraction you used as its name.
```auto
mix_fast = openmc.Material.mix_materials([UO2, PuO2, SUS, sodium], [0.56, 0.14, 0.1, 0.2], 'wo')
# mix_fast = openmc.Material.mix_materials([UO2, PuO2, SUS, sodium], [0.56, 0.14, 0.1, 0.2], 'wo', name = 'Homogenised Fast Material')
mix_fast
```
after that, I can use the material in my plot
---
### Author:  [@danii](https://openmc.discourse.group/u/danii)
#### Post date: [September 16, 2024, 7:04am UTC](https://openmc.discourse.group/t/struggling-to-plot-geometry-with-mix-materials/4798/3 "2024-09-16T07:04:53Z")
thank you very much sir! may God ease all your ways
---
### Author:  [@wahidluthfi](https://openmc.discourse.group/u/wahidluthfi)
#### Post date: [September 16, 2024, 10:37pm UTC](https://openmc.discourse.group/t/struggling-to-plot-geometry-with-mix-materials/4798/4 "2024-09-16T22:37:56Z")
Whoaa, thanks, may all good things come to you