Htoa saves the file and the material is lost.

What version of HtoA houdini do you see this?

Are there any errors in the console?

houdini17.5.327 and htoa4.2.0There is no prompt, as long as the houdini file is saved, all the materials are lost when you open the houdini file you just saved.

Who can answer this question, sincerely ask for advice. If it is a bug, depending on the official's intention to fix it, this problem has been more than two months. It seems that the official also directly ignores my problem, but it is really confused, even if it is a bug, I hope the official will say it.

Work fine here
For sure there is something wrong in your houdini.env file.
Do you have any others renderer like: Redshift, Octane, Renderman?

I recorded a silent video and I understood it at a glance。https://vimeo.com/351411244

A 9 minute video? You say you know the problem. Can't you just write down the problem?

It should be that I express the problem. I mean that since I know the problem, if I can open the program, I should be able to find the problem. Look at the specific problem caused by the code. This reason is definitely not related to the path of the .env file in the houdini documentation. Thank you for your help. It has been plagued by this problem for a long time. This problem has been encountered in the project for half a year. I also hope that htoa is getting better and better. If the official development is not so busy, you can look at the specific reasons. Thanks to htoa official. Great renderer. The company has been using htoa to make projects for three years.

To avoid conflicts with other rendering engines,it is best to use json file for each renderer like
Arnold.json
Redshift.json
Vray.json
Corona.json
Renderman.json
etc..

Leave Houdini.env file empty, do not put anything in it

Create packages folder inside "C:\Users\Your_USER_NAME\Documents\houdini17.5" and put all your json file

#Here is one for Arnold.json
{
"env":
[
{
"PATH":
[
"C:/Users/rachid/htoa/htoa-4.2.0_rcd74057_houdini-17.5.327/htoa-4.2.0_rcd74057_houdini-17.5.327/scripts/bin;"
]
},
{
"HOUDINI_PATH":
[
"C:/Users/rachid/htoa/htoa-4.2.0_rcd74057_houdini-17.5.327/htoa-4.2.0_rcd74057_houdini-17.5.327"
]
},
{
"ARNOLD_PLUGIN_PATH":
[
"C:/Arnold_Shader/alShaders/bin;C:/Arnold_Shader/Octoplug/bin;C:/Arnold_Shader/pota/bin;C:/Arnold_Shader/dusty/bin;C:/Arnold_Shader/Osl/bin;"
]
}
]
}

########## Redshift.json
{
"env":
[
{
"PATH":
[
"C:/ProgramData/Redshift/bin;"
]
},
{
"HOUDINI_PATH":
[
"C:/ProgramData/Redshift/Plugins/Houdini/17.5.327"
]
}
]
}

########## Renderman.json
{
"env":
[
{
"RFHTREE":
[
"C:/Program Files/Pixar/RenderManForHoudini-22.6"
]
},
{
"RMANTREE":
[
"C:/Program Files/Pixar/RenderManProServer-22.6"
]
},
{
"PATH":
[
"C:/Program Files/Pixar/RenderManProServer-22.6/bin;"
]
},
{
"HOUDINI_PATH":
[
"C:/Program Files/Pixar/RenderManForHoudini-22.6/17.5"
]
}
]
}

The only conflict even with json.file is with Arnold/Renderman
The solution is simply load Arnold or Renderman (by renaming Arnold.json to something like Arnold.json_Backup or Renderman.json to Renderman.json_XX )
Hope this help

This is not the problem. Why do you always think of this kind of problem? The document that houdini always thinks about. The arnold path of the .evn file is wrong, or it conflicts with other ones! The first is even a conflict. How did these conflicts before? Second, even if you only install arnold without installing any other renderers, the material will not be the same and will be lost. Isn't there a real fundamental solution? Everything is simple. The blow can be tested directly, just install htoa and you will understand.

So the issue is with loading the scene by double-clicking the file in windows it to load houdini?