feat: Hierarchical Model Importer #2898
Conversation
. 1. Changes to MeshConvertor and MeshAssetImporter to be able to import sub meshes in model as individual models in project assets
Checkbox option for split at time of import
With all fixes suggested stride3d#2553 (comment)
Eideren
changed the title
@dotnet-policy-service agree |
|
Looks like materials are not handled properly: every individual object is set to the same material. The prefab's hierarchy is almost right, there is an additional Here's the file I used for testing - this is not CC0, do not use in projects. |
|
Thanks for sharing the test file. I’ve checked in updates, and both issues are now fixed:
|
|
We're back to the previous issue with the materials, we need to only have the materials that are assigned to an object on that object, not every material that was contained in the original scene. Also, the pivot position for individual models is not retained, they all have their pivot set to the origin instead of wherever it actually is in the file. |
|
are you on latest? it imports fine my side 
|
|
The vertices are at the right position in world space, but each mesh's pivot point is not right below the model, like it is in the file, it is set to the origin. |
|
Makes sense, thanks for pointing out, This is now fixed. With this latest-
|
There was a problem hiding this comment.
You haven't thoroughly gone through the LLM's work there it seems, there's a fairly large amount of redundant logic, and comments that are clearly targeted at someone interacting with an LLM, not at describing the logic being implemented.
I'm okay with reviewing someone's work, not going over what an LLM spit out, that is your burden to carry - and you're definitely capable of that, I have seen you write better stuff than this.
I haven't gone through the whole thing yet, but do go over your entire PR and clean things up, there's a lot of low hanging fruits I have not marked.
You could also look into using/enabling nullable, there's a bunch of null checks and tests that are redundant or definitely should throw in the null case.
| if (splitHierarchy) | ||
| { | ||
| var entityInfo = importer.GetEntityInfo(file, parameters.Logger, importParameters); | ||
| if (entityInfo != null && (entityInfo.Models?.Count ?? 0) > 0) |
There was a problem hiding this comment.
Can be simplified if (entityInfo?.Models?.Count > 0)
|
|
||
|
|
||
| // No combined "(All)" model when splitting; Prefab is the combined representation | ||
| AssetItem allModelAsset = null; |
There was a problem hiding this comment.
fixed, no longer needed
| // Build prefab using the per-mesh models in the same order we created them | ||
| var perMeshModels = perMeshAssets; | ||
|
|
||
|
|
||
| for (int i = 0; i < entityInfo.Models.Count; i++) | ||
| { | ||
| var item = perMeshModels[i]; | ||
| if (item?.Asset is ModelAsset modelAsset) | ||
| { | ||
| TrimModelAssetToSingleMaterialByIndex(modelAsset, | ||
| entityInfo.Models[i].OriginalMaterialIndex); // <- the index from step 1 | ||
| } | ||
| } |
There was a problem hiding this comment.
Looks like splitting into a new loop is unnecessary, you could just append that logic at line 212 ? And then remove perMeshAssets ?
There was a problem hiding this comment.
fixed with new mesh to material mapping
| asset.Materials.Add(keep); | ||
| } | ||
|
|
||
| private static AssetItem BuildPrefabForSplitHierarchy(string baseName, EntityInfo entityInfo, IList<AssetItem> perMeshModels, AssetItem allModelAsset, UDirectory targetLocation) |
There was a problem hiding this comment.
Annotate return type with CanBeNull, remove AssetItem allModelAsset parameter
| else | ||
| { | ||
| // Split OFF: keep a single Model named exactly after the source file (no "(All)") | ||
| var idx = assets.FindIndex(a => a.Asset is ModelAsset); | ||
| if (idx >= 0) | ||
| { | ||
| var old = assets[idx]; | ||
| assets.RemoveAt(idx); | ||
|
|
||
| // Assign a fresh Id to the single model to avoid any Id collisions | ||
| ((ModelAsset)old.Asset).Id = AssetId.New(); // <<—— ensure unique Id | ||
|
|
||
| var uniqueFile = MakeUniqueFileName(baseName, assets); | ||
| var renamed = new AssetItem(UPath.Combine(parameters.TargetLocation, uniqueFile), old.Asset); | ||
| assets.Insert(idx, renamed); | ||
| } | ||
| } |
There was a problem hiding this comment.
Shouldn't the case for splitHierarchy == false be left untouched, what is this fixing exactly ?
There was a problem hiding this comment.
it was only there to seperate account for (all) model when in prefab and the legacy flow, but since thats not needed so removed
| private static void TrimModelAssetToSingleMaterialByIndex(ModelAsset asset, int keepIndex) | ||
| { | ||
| if (asset?.Materials == null) return; | ||
| if (keepIndex < 0 || keepIndex >= asset.Materials.Count) return; | ||
|
|
||
| var keep = asset.Materials[keepIndex]; | ||
| asset.Materials.Clear(); | ||
| asset.Materials.Add(keep); | ||
| } |
There was a problem hiding this comment.
A single model should be able to have more than one material assigned to it, this is not the source of the issue obviously, something else earlier in the call chain doesn't handle it appropriately. Here an example where I simply assigned a second material to the bookend mesh:
Here's the file
There was a problem hiding this comment.
Fixed, by storing material to mesh mapping at entityinfo level as ground truth
sources/editor/Stride.Assets.Presentation/Templates/ModelFromFileTemplateGenerator.cs
Show resolved
Hide resolved
| if (!nodeNameToIndex.TryGetValue(meshInfo.NodeName, out var nodeIndex)) | ||
| continue; |
There was a problem hiding this comment.
Shouldn't this be an exception ? If this fail we would silently ignore one of the models ?
| { | ||
| if (!extraChildCountByNode.TryGetValue(nodeIndex, out var k)) | ||
| k = 0; | ||
| k++; |
There was a problem hiding this comment.
rename k to something more explicit
There was a problem hiding this comment.
fixed, renamed it to counter
| var firstName = firstNode.Name ?? string.Empty; | ||
| bool looksLikeWrapper = | ||
| string.IsNullOrWhiteSpace(firstName) | ||
| || firstName.Equals(baseName, StringComparison.OrdinalIgnoreCase) | ||
| || firstName.Equals("RootNode", StringComparison.OrdinalIgnoreCase); |
There was a problem hiding this comment.
Redudant firstName, you're already testing for null in looksLikeWrapper, change to
bool looksLikeWrapper =
string.IsNullOrWhiteSpace(firstNode.Name)
|| firstNode.Name.Equals(baseName, StringComparison.OrdinalIgnoreCase)
|| firstNode.Name.Equals("RootNode", StringComparison.OrdinalIgnoreCase);
Got it. I was focusing on getting it fully functional before moving on to cleanup and optimization, since the prefab generation feature is a bit tricker than I anticipated. I’ve removed any mechnical commets. Committed the latest version with fixes and a cleaner codebase @Eideren |
|
Throws in |
…shConvertor Level
|
No more string manipulations by storing source mesh name variable in ModelAsset, checked in latest @Eideren |
|
Most of my comments have not been addressed, moving this to draft while you take care of those. Feel free to set it to ready once it is actually ready for review. |
|
The one I mentioned there as I said #2898 (comment) - Changing the name of a model asset in the editor changes the actual mesh that gets imported |
|
My mistake, overlooked that part. I’ve checked in updates, storing mesh ID as a key pointer in ModelAsset, which is set only once at time of creation and remains unchanged on renaming etc. @Eideren |
|
If I select this option from the context menu, the model has a bunch of new entries created for its materials instead of just the ones used |
|
Fixed. It still reimports the mesh upon update from source but will not add extra materials @Eideren |
|
If a model has multiple materials assigned it ends up being split across two models |
|
Can you tell which mesh to look for in structure? And you mean if material has multiple materials its only applying first one? |
|
There are two cushions on the bed, one of them is of the same material as the bed, while the other has a different one assigned to it, both of them are part of the bed model in the original fbx file. |
|
Fixed material mapping mismatch between Stride and Assimp. |
|
There's another fairly obvious issue you've introduced with the latest changes, didn't even have to do anything this time around, import your model and test things out properly. |
|
Just tested, its loading fine for me, can you tell whats the problem? @Eideren |
|
It's visible on your screen, half of the furniture is not on the right spot in the prefab |
|
I see, its going in circle, if I try to match exact materials than meshs dont position correctly if set mesh then materials dont set up correctly, ideally classes should have set up keeping multiple material in mind, i can try some more but not sure. If its acceptable to have only one material material imported like it is now, it will require only more additional stepon users part to assign the extra material on mesh in user interface? |
|
If it's not a bug but a limitation in the design, sure, but that's not really the case here. You'll figure it out I'm sure ! |
|
Think I got it working, here is side by side of stride import vs blender import @Eideren 
|
|
Looks like it's almost ready for me to review the code, just have to fix two edge case I found:
You can use this new file to test the second issue: Untitled.zip |
The problem with second issue is update pipeline and the initial creation pipeline are different. Even in existing import system (apart from split-hierarchy), “Update from Source” only refreshes the existing model asset — it does not pass through ModelFromFileTemplateGenerator, so no new material assets are generated on update. The initial import pipeline uses ModelFromFileTemplateGenerator, which handles material creation and asset registration. Changing this behavior may take a larger architectural update to unify the import and update logic. May be for now, we can keep the current behavior as-is and create a separate task or future update for this. Please advice. @Eideren |
Yep, I did notice that it doesn't create a new material asset, but it still creates a new material entry on the model asset, which is why I'm not asking you to support the former, but only the latter. |
|
Just so I understand, by entry you mean additional empty or default
material slots on model one for each material in source mesh ?
…On Mon 3. Nov 2025 at 17:21, Eideren ***@***.***> wrote:
*Eideren* left a comment (stride3d/stride#2898)
<#2898 (comment)>
so no new material assets are generated on update
Yep, I did notice that it doesn't create a *new material asset*, but it
still creates a *new material entry* on *the model asset*, which is why
I'm not asking you to support the former, but only the latter.
—
Reply to this email directly, view it on GitHub
<#2898 (comment)>,
or unsubscribe
<https://github.com/notifications/unsubscribe-auth/AF5T3B6QO2ITAKYSOLWKYOD325XJLAVCNFSM6AAAAACGW4SEGGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTIOBRGA4DSMRSGA>
.
You are receiving this because you were mentioned.Message ID:
***@***.***>
|
|
The entries highlighted here |
|
Its the same reason, the sub model assets with split hierarchy are not real items with independent source makes them different, the material slots are set in ModelFromFileTemplateGenerator. May be I can find something to show up materials and make it work but not sure how far Updating such virtual assets individually this way will work |
|
Checked in update to best accommodate this, it should show empty slots based on asset but I am not sure how much it would hold as updating material this way can lead to potential problems. The structure of imported file after changing materials is different in terms of how mesh and fbx nodes are connected to sync back with data original file in terms of matching which mesh and material to current comes with all sorts of problems to account all ways it changed, naming, order, hierarchy or any other way user can tinker file in 3d model tool. Updating entire model (split hierarchy) from source works as part wise match to what exiting is not needed! |
|
Welp, it does add new entries for new material, but it doesn't remove ones that are not part of the model anymore |
|
I'm not sure what more can be done here, updating hierarchical import from source once imported is not a right and will not work, it has to be done manually |
2 participants
This PR adds an “Split hierarchy” workflow for model import: when enabled, Stride imports one Model per mesh (named after the mesh) and automatically generates a Prefab that mirrors the FBX node hierarchy. When disabled, the import produces a single combined Model (no “(All)” suffix).
What’s in this PR-
Split hierarchy checkbox in Add asset → 3D model dialog.
Remembers last value per project.
Behavior (per mode)
Split hierarchy = ON
Imports N Model assets (one per mesh) named:
"-" (sanitized; auto-uniquified with -1, -2, …).
Creates a Prefab named " Prefab" that replicates the FBX hierarchy (one Entity per node, correct parent/child relationships).
Each Entity that hosts a mesh gets a ModelComponent referencing the corresponding per-mesh Model.
Each per-mesh Model keeps only the material(s) it actually uses\
Split hierarchy = OFF
Imports a single Model named exactly ""