# Material declaration in mental ray

**URL:** https://forum.highend3d.com/t/material-declaration-in-mental-ray/61023
**Category:** Xsi
**Tags:** developers
**Created:** [December 16, 2004, 2:46pm UTC](https://forum.highend3d.com/t/material-declaration-in-mental-ray/61023 "2004-12-16T14:46:26Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![sascha-1](https://forum.highend3d.com/letter_avatar_proxy/v4/letter/s/e480ec/32.png) [@sascha-1](https://forum.highend3d.com/u/sascha-1)
#### Post date: [December 16, 2004, 2:46pm UTC](https://forum.highend3d.com/t/material-declaration-in-mental-ray/61023/1 "2004-12-16T14:46:26Z")

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I have my problems with specifying the material for a polygon in a geometry object group. If I pass miNULLTAG the polygons should inherit the material from the placeholder I think. Unfortunately this does only happen when passing an object to the shader without having use for it. So how can I force XSI to pass the material to mental ray? Or is there another way to access the inherited material in the database?