# Voxel sampling rate for optimisation?
**URL:** https://opentps.discourse.group/t/voxel-sampling-rate-for-optimisation/27
**Category:** General
**Created:** [July 5, 2024, 2:31pm UTC](https://opentps.discourse.group/t/voxel-sampling-rate-for-optimisation/27 "2024-07-05T14:31:05Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Wens](https://opentps.discourse.group/u/Wens)
#### Post date: [July 5, 2024, 2:31pm UTC](https://opentps.discourse.group/t/voxel-sampling-rate-for-optimisation/27/1 "2024-07-05T14:31:05Z")
One thing I do not understand is the resolution/sampling rate that is used in optimisation. Where is that set and what are the defaults?
Suppose I have a very large OAR/CTV/structure, and I only want 20% of the voxels for optimisation, i.e. dose influence matrices for 20% of the volume. Is that somehow possible to configure?
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### Author:  [@sowuy](https://opentps.discourse.group/u/sowuy)
#### Post date: [July 8, 2024, 7:44am UTC](https://opentps.discourse.group/t/voxel-sampling-rate-for-optimisation/27/2 "2024-07-08T07:44:09Z")
Hi Wens,
Welcome to OpenTPS and thanks for contributing with your question.
Here is an answer:
We do not support **yet** a parameter that sets the % of voxels on which you want to optimize. I suppose you are referring to DVH optimization functions (e.g. D1\<20Gy) ? Nevertheless, we are organizing an “OpenTPS camp” internally in 2 weeks and the implementation of such functions has high priority. It should therefore be merged into master by the end of the month.
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### Author:  [@sowuy](https://opentps.discourse.group/u/sowuy)
#### Post date: [August 1, 2024, 9:17am UTC](https://opentps.discourse.group/t/voxel-sampling-rate-for-optimisation/27/3 "2024-08-01T09:17:52Z")
Hi @Wens,
DVH objectives (among others) have now been added for plan optimization and merged to the master branch (Merge request [!164](https://gitlab.com/openmcsquare/opentps/-/merge_requests/164)). Let us know if it run into into any trouble