# Fail to generate the ASENS file in CMAQ-DDM V5.4

**URL:** <https://forum.cmascenter.org/t/fail-to-generate-the-asens-file-in-cmaq-ddm-v5-4/4005>\
**Category:** CMAQ-DDM-3D\
**Created:** [March 23, 2023, 11:12pm UTC](https://forum.cmascenter.org/t/fail-to-generate-the-asens-file-in-cmaq-ddm-v5-4/4005 "2023-03-23T23:12:50Z")\
**Posts on this page:** 1\
**Showing post:** 16

<div class="post-metadata">

**Author:** ![hogrefe.christian](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@hogrefe.christian](https://forum.cmascenter.org/u/hogrefe.christian)\
**Post date:** [September 19, 2024, 12:55pm UTC](https://forum.cmascenter.org/t/fail-to-generate-the-asens-file-in-cmaq-ddm-v5-4/4005/16 "2024-09-19T12:55:19Z")

</div>

If you do not define any region-specific sensitivity parameters in your sensinput.dat control file, you will not need to define a CMAQ\_MASKS file in your CCTM run script and you then also should not uncomment any lines referring to CMAQ\_MASKS in the `&Desid_RegionDef` section of CMAQ\_Control\_DESID.nml

If you do want to specify sensitivity parameters for specific regions, you will need to set these variables and point them to a corresponding file defining these regions. Region files used in DESID emissions scaling as well as DDM-3D and ISAM are described in [Appendix B](https://github.com/USEPA/CMAQ/blob/main/DOCS/Users_Guide/Appendix/CMAQ_UG_appendixB_emissions_control.md#b342-defining-regions).

You can also search this forum for previous threads discussing approaches to create such files by using a search term of “mask” or “region”, e.g. [here](https://forum.cmascenter.org/t/how-to-make-isam-regions-file/2877) or [here](https://forum.cmascenter.org/t/whats-the-maskdatas-format/2919)

---

_[View the full topic](https://forum.cmascenter.org/t/fail-to-generate-the-asens-file-in-cmaq-ddm-v5-4/4005)._