Hello everybody. I'm currently having an issue with exporting normal maps with the texture sheet node in houdini 18.5. I've been looking for solutions on the internet. I saw that a lot of people had more or less similar issues exporting normals or just vizualising them but I couldn't find the solution of my specific problem after reading these posts and watching tutorials so I come to you...

I'm making an explosion (so I have smoke (density) and fire) and I managed to export color maps, and packed maps to UE4 (I have colors, normalized emissive, alpha) however I don't have any normals on my red and green channels of the packed maps while normals do appear when I look at the N channel of my texture sheet in MPlay.


(this is a frame of the simulation)


(this is the normals of the frame viewed in Mplay)


(this is the aspect of the normals when exported)

Just in case here is the setup I had for creating the simulation :


I followed all the steps of the base texture sheet export provided by sideFX (using a base Mantra plugged into a texture sheet) and I watched it again a lot of times and it didn't work any differently. I made sure that what i'm exporting has density, that lights where present on the scene and nothing changed the result. The look of the simulation is quite great for what it is inside of UE4 but it still feels flat because I don't have normal informations on it, this is the last thing I need to make it work.

I'm out of solutions right now... So if anybody has an idea of what could provoke this I could use some advice please.

Update :
I just tried a new export with another simulation but this time I exported as exr file instead of png (I exported in png because i had problems reading exr files on my pc and it was faster to see if my exports were doing well) and the export seems to work better. It looks like I have normal informations in my red and green channels !

I'm going to try another export with the simulation I presented on my previous post and see how it works !

PROBLEM SOLVED :

So I did that new export with the explosion simulation I had issues with but this time in exr format and it worked ! I think maybe I messed something up when I tried to change the format from exr to png in the first place. In any case my problem is solved I hope maybe it could help anybody having the same issue as me.