По всей видимости, нужно ставить последний мадбокс, либо перебрасывай модели просто через экспорт в FBX
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NoteMaya has a similar feature for exporting files to Mudbox (File > Export Selected to Mudbox). For more information, refer to the Maya Help. The Export Selected to Mudbox feature is not compatible with versions of Mudbox earlier than Mudbox 2011. FBX files exported from Maya 2011 are not compatible with Mudbox versions earlier than Mudbox 2011 unless an earlier FBX version is specified in the FBX export options.
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