diff --git a/code/AssetLib/Obj/ObjFileData.h b/code/AssetLib/Obj/ObjFileData.h
index bc65058ac..3d504d0bb 100644
--- a/code/AssetLib/Obj/ObjFileData.h
+++ b/code/AssetLib/Obj/ObjFileData.h
@@ -195,6 +195,9 @@ struct Material {
     //! PBR Anisotropy
     ai_real anisotropy;
 
+    //! bump map multipler (normal map scalar)(-bm)
+    ai_real bump_multiplier;
+
     //! Constructor
     Material() :
             diffuse(ai_real(0.6), ai_real(0.6), ai_real(0.6)),
@@ -208,7 +211,8 @@ struct Material {
             sheen(ai_real(1.0), ai_real(1.0), ai_real(1.0)),
             clearcoat_thickness(ai_real(0.0)),
             clearcoat_roughness(ai_real(0.0)),
-            anisotropy(ai_real(0.0)) {
+            anisotropy(ai_real(0.0)),
+            bump_multiplier(ai_real(1.0)) {
         std::fill_n(clamp, static_cast<unsigned int>(TextureTypeCount), false);
     }
 
diff --git a/code/AssetLib/Obj/ObjFileImporter.cpp b/code/AssetLib/Obj/ObjFileImporter.cpp
index fd062552f..6dd26956e 100644
--- a/code/AssetLib/Obj/ObjFileImporter.cpp
+++ b/code/AssetLib/Obj/ObjFileImporter.cpp
@@ -51,6 +51,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <assimp/scene.h>
 #include <assimp/DefaultLogger.hpp>
 #include <assimp/Importer.hpp>
+#include <assimp/ObjMaterial.h>
 #include <memory>
 
 static const aiImporterDesc desc = {
@@ -657,6 +658,9 @@ void ObjFileImporter::createMaterials(const ObjFile::Model *pModel, aiScene *pSc
         if (0 != pCurrentMaterial->textureBump.length) {
             mat->AddProperty(&pCurrentMaterial->textureBump, AI_MATKEY_TEXTURE_HEIGHT(0));
             mat->AddProperty(&uvwIndex, 1, AI_MATKEY_UVWSRC_HEIGHT(0));
+            if (pCurrentMaterial->bump_multiplier != 1.0) {
+                mat->AddProperty(&pCurrentMaterial->bump_multiplier, 1, AI_MATKEY_OBJ_BUMPMULT_HEIGHT(0));
+            }
             if (pCurrentMaterial->clamp[ObjFile::Material::TextureBumpType]) {
                 addTextureMappingModeProperty(mat, aiTextureType_HEIGHT);
             }
@@ -665,6 +669,9 @@ void ObjFileImporter::createMaterials(const ObjFile::Model *pModel, aiScene *pSc
         if (0 != pCurrentMaterial->textureNormal.length) {
             mat->AddProperty(&pCurrentMaterial->textureNormal, AI_MATKEY_TEXTURE_NORMALS(0));
             mat->AddProperty(&uvwIndex, 1, AI_MATKEY_UVWSRC_NORMALS(0));
+            if (pCurrentMaterial->bump_multiplier != 1.0) {
+                mat->AddProperty(&pCurrentMaterial->bump_multiplier, 1, AI_MATKEY_OBJ_BUMPMULT_NORMALS(0));
+            }
             if (pCurrentMaterial->clamp[ObjFile::Material::TextureNormalType]) {
                 addTextureMappingModeProperty(mat, aiTextureType_NORMALS);
             }
diff --git a/code/AssetLib/Obj/ObjFileMtlImporter.cpp b/code/AssetLib/Obj/ObjFileMtlImporter.cpp
index 7d5930594..2441c17f2 100644
--- a/code/AssetLib/Obj/ObjFileMtlImporter.cpp
+++ b/code/AssetLib/Obj/ObjFileMtlImporter.cpp
@@ -472,7 +472,11 @@ void ObjFileMtlImporter::getTextureOption(bool &clamp, int &clampIndex, aiString
             }
 
             skipToken = 2;
-        } else if (!ASSIMP_strincmp(pPtr, BlendUOption.c_str(), static_cast<unsigned int>(BlendUOption.size())) || !ASSIMP_strincmp(pPtr, BlendVOption.c_str(), static_cast<unsigned int>(BlendVOption.size())) || !ASSIMP_strincmp(pPtr, BoostOption.c_str(), static_cast<unsigned int>(BoostOption.size())) || !ASSIMP_strincmp(pPtr, ResolutionOption.c_str(), static_cast<unsigned int>(ResolutionOption.size())) || !ASSIMP_strincmp(pPtr, BumpOption.c_str(), static_cast<unsigned int>(BumpOption.size())) || !ASSIMP_strincmp(pPtr, ChannelOption.c_str(), static_cast<unsigned int>(ChannelOption.size()))) {
+        } else if (!ASSIMP_strincmp(pPtr, BumpOption.c_str(), static_cast<unsigned int>(BumpOption.size()))) {
+            DataArrayIt it = getNextToken<DataArrayIt>(m_DataIt, m_DataItEnd);
+            getFloat(it, m_DataItEnd, m_pModel->m_pCurrentMaterial->bump_multiplier);
+            skipToken = 2;
+        } else if (!ASSIMP_strincmp(pPtr, BlendUOption.c_str(), static_cast<unsigned int>(BlendUOption.size())) || !ASSIMP_strincmp(pPtr, BlendVOption.c_str(), static_cast<unsigned int>(BlendVOption.size())) || !ASSIMP_strincmp(pPtr, BoostOption.c_str(), static_cast<unsigned int>(BoostOption.size())) || !ASSIMP_strincmp(pPtr, ResolutionOption.c_str(), static_cast<unsigned int>(ResolutionOption.size())) || !ASSIMP_strincmp(pPtr, ChannelOption.c_str(), static_cast<unsigned int>(ChannelOption.size()))) {
             skipToken = 2;
         } else if (!ASSIMP_strincmp(pPtr, ModifyMapOption.c_str(), static_cast<unsigned int>(ModifyMapOption.size()))) {
             skipToken = 3;
diff --git a/include/assimp/ObjMaterial.h b/include/assimp/ObjMaterial.h
new file mode 100644
index 000000000..39894a696
--- /dev/null
+++ b/include/assimp/ObjMaterial.h
@@ -0,0 +1,77 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file OBJMATERIAL.h
+ *  @brief Obj-specific material macros
+ *  
+ */
+
+#ifndef AI_OBJMATERIAL_H_INC
+#define AI_OBJMATERIAL_H_INC
+
+#ifdef __GNUC__
+#   pragma GCC system_header
+#endif
+
+#include <assimp/material.h>
+
+// ---------------------------------------------------------------------------
+// Pure key names for all obj texture-related properties
+//! @cond MATS_DOC_FULL
+
+// support for bump -bm 
+#define _AI_MATKEY_OBJ_BUMPMULT_BASE "$tex.bumpmult"
+//! @endcond
+
+// ---------------------------------------------------------------------------
+#define AI_MATKEY_OBJ_BUMPMULT(type, N) _AI_MATKEY_OBJ_BUMPMULT_BASE, type, N
+
+//! @cond MATS_DOC_FULL
+#define AI_MATKEY_OBJ_BUMPMULT_NORMALS(N) \
+    AI_MATKEY_OBJ_BUMPMULT(aiTextureType_NORMALS, N)
+
+#define AI_MATKEY_OBJ_BUMPMULT_HEIGHT(N) \
+    AI_MATKEY_OBJ_BUMPMULT(aiTextureType_HEIGHT, N)
+
+//! @endcond
+
+
+#endif