# Combine Models Unable to execute correctly

**URL:** <https://discourse.slicer.org/t/combine-models-unable-to-execute-correctly/26375>\
**Category:** Development\
**Created:** [November 22, 2022, 11:26am UTC](https://discourse.slicer.org/t/combine-models-unable-to-execute-correctly/26375 "2022-11-22T11:26:48Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![miniminic](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/miniminic/32/16647_2.png) [@miniminic](https://discourse.slicer.org/u/miniminic)\
**Post date:** [November 22, 2022, 11:26am UTC](https://discourse.slicer.org/t/combine-models-unable-to-execute-correctly/26375/1 "2022-11-22T11:26:48Z")

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![屏幕截图 2022-11-22 192910](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/d/2/d261dd39c96187f5c7c6625996c4ba0a892a1314.jpeg)  
 ![屏幕截图 2022-11-22 192942](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/9/9/9916d7072c443e79b6686201e10d96e8137ff7fb.jpeg)  
I load two models Result Part\_1 is part of the “静脉” Model, then I do A-B on both models, but the resulting model is empty. I have to add A transformation to one of the models and move it around, and then do A-B to get the right result  
 ![屏幕截图 2022-11-22 192324](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/1/0/10c8fa3cb05bccc4746fe31f1ed607bd0026891d.jpeg)  
 ![屏幕截图 2022-11-22 192343](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/d/e/de4e3f8c9bd417aa0b82e43c5fdc93ca2c63b77f.jpeg)  
It feels like when you add two overlapping Models, you can’t use Combine Models directly, you have to move them around before you can use that module

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [December 1, 2022, 6:28am UTC](https://discourse.slicer.org/t/combine-models-unable-to-execute-correctly/26375/2 "2022-12-01T06:28:57Z")

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You can submit an issue to the vtkbool repository, providing download links to the two meshes to get information about why the operation fails. Maybe it is due to almost all faces of the meshes coinciding.

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<div class="post-metadata">

**Author:** ![miniminic](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/miniminic/32/16647_2.png) [@miniminic](https://discourse.slicer.org/u/miniminic)\
**Post date:** [December 1, 2022, 7:52am UTC](https://discourse.slicer.org/t/combine-models-unable-to-execute-correctly/26375/3 "2022-12-01T07:52:41Z")

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Yeah it looks like vtkbool doesn’t work when set a is a member of set b.