What solutions have you tried so far? Did you look for solutions on the Developer Hub?
I searched in Dev Forum but couldn’t find the solution.
After that, you should include more details if you have any. Try to make your topic as descriptive as possible, so that it’s easier for people to help you!
I want to change the direction of the wood material 90 degrees on the handle part of the hammer cause it looks unnatural now.
Definitely consider checking out @stravant’s MaterialFlip Plugin to help with this directional issue. Not sure if it’s Meshpart supported but you can try it out.
That looks like a MeshPart. Did you make it yourself and have a model available of it?
If not, make sure the handle’s orientation is 0,0,0, then right-click on it in the Explorer and hit “Export Selection” and import it into Blender.
Go into Edit Mode, rotate it into the same orientation as your hammer’s head (so 90 degrees), go back into Object Mode, hit Ctrl+A, select “Apply all transforms”, and then export it.
When you now import it into Roblox, the material should now be aligned how you want it to.