Nesting Collection instances cause first objects to disappear (restricted by MAX_DUPLI_RECUR) #89844

New Issue

Jon · 2021-07-13T22:30:17+02:00

Jon commented

2021-07-13 22:30:17 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 970/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71

Blender Version
Broken: version: 2.93.1, branch: master, commit date: 2021-06-22 05:57, hash: 1b8d33b18c

Short description of error
Ten levels of collection instances cause the base object to become invisible. Steps to recreate the issue are:

1: Create a collection "Collection 1" and add a mesh object to it.
2: Create a collection "Collection 2" and add an instance of "Collection 1" to it.
3: Continue repeating step 2) of adding of adding nested collection instances, until collection "Collection 10" contains an instance of "Collection 9".
4: Create a collection instance of "Collection 10" and hide all other collections. The mesh object in "Collection 1" will no longer visible (or rendered).
5: If a mesh object is added to "Collection 2", it becomes visible in the "Collection 10" instance but disappears from a "Collection 11" instance, if created.

This bug has been in Blender since collections were first added and its unusual for a project to have 10 levels of collection instances, so it doesn't normally cause a problem. If this is 'correct' behaviour it would be nice if a warning message was displayed to users explaining that the base objects wont be rendered.

Exact steps for others to reproduce the error
Open the linked file and no mesh will be displayed for the "Collection 10" collection instance. If its "Object Properties → Instancing → Collection" field is edited to "Collection 9", then the mesh will become visible.

NestedCollectionBug.blend

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 970/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71 **Blender Version** Broken: version: 2.93.1, branch: master, commit date: 2021-06-22 05:57, hash: `1b8d33b18c` **Short description of error** Ten levels of collection instances cause the base object to become invisible. Steps to recreate the issue are: 1: Create a collection "Collection 1" and add a mesh object to it. 2: Create a collection "Collection 2" and add an instance of "Collection 1" to it. 3: Continue repeating step 2) of adding of adding nested collection instances, until collection "Collection 10" contains an instance of "Collection 9". 4: Create a collection instance of "Collection 10" and hide all other collections. The mesh object in "Collection 1" will no longer visible (or rendered). 5: If a mesh object is added to "Collection 2", it becomes visible in the "Collection 10" instance but disappears from a "Collection 11" instance, if created. This bug has been in Blender since collections were first added and its unusual for a project to have 10 levels of collection instances, so it doesn't normally cause a problem. If this is 'correct' behaviour it would be nice if a warning message was displayed to users explaining that the base objects wont be rendered. **Exact steps for others to reproduce the error** Open the linked file and no mesh will be displayed for the "Collection 10" collection instance. If its "Object Properties → Instancing → Collection" field is edited to "Collection 9", then the mesh will become visible. [NestedCollectionBug.blend](https://archive.blender.org/developer/F10223485/NestedCollectionBug.blend)

Jon commented

2021-07-13 22:30:17 +02:00

Added subscriber: @StraumliBlight

Philipp Oeser commented

2021-08-30 13:55:57 +02:00

Added subscribers: @mont29, @brecht, @lichtwerk

Philipp Oeser commented

2021-08-30 13:55:57 +02:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'

Philipp Oeser commented

2021-08-30 13:55:57 +02:00

Can confirm the behavior.

This seems to be restricted by MAX_DUPLI_RECUR.
Changing this might be possible (needs to be done in a couple of places, see the following patch), but I assume there will be issues with persistent_id then (that I cannot forsee).

P2350: T89844_snippet



diff --git a/intern/cycles/blender/blender_id_map.h b/intern/cycles/blender/blender_id_map.h
index 198cfb4b29a..aed18b44e21 100644
--- a/intern/cycles/blender/blender_id_map.h
+++ b/intern/cycles/blender/blender_id_map.h
@@ -196,7 +196,7 @@ template<typename K, typename T> class id_map {
  * To uniquely identify instances, we use the parent, object and persistent instance ID.
  * We also export separate object for a mesh and its particle hair. */
 
-enum { OBJECT_PERSISTENT_ID_SIZE = 8 /* MAX_DUPLI_RECUR in Blender. */ };
+enum { OBJECT_PERSISTENT_ID_SIZE = 10 /* MAX_DUPLI_RECUR in Blender. */ };
 
 struct ObjectKey {
   void *parent;
diff --git a/source/blender/blenkernel/BKE_duplilist.h b/source/blender/blenkernel/BKE_duplilist.h
index c142d5338d1..d3e3ad9a0f1 100644
--- a/source/blender/blenkernel/BKE_duplilist.h
+++ b/source/blender/blenkernel/BKE_duplilist.h
@@ -51,7 +51,7 @@ typedef struct DupliObject {
 
   /* Persistent identifier for a dupli object, for inter-frame matching of
    * objects with motion blur, or inter-update matching for syncing. */
-  int persistent_id- [x]; /* MAX_DUPLI_RECUR */
+  int persistent_id[10]; /* MAX_DUPLI_RECUR */
 
   /* Particle this dupli was generated from. */
   struct ParticleSystem *particle_system;
diff --git a/source/blender/draw/engines/eevee/eevee_private.h b/source/blender/draw/engines/eevee/eevee_private.h
index f51b4fa0127..fe719084a61 100644
--- a/source/blender/draw/engines/eevee/eevee_private.h
+++ b/source/blender/draw/engines/eevee/eevee_private.h
@@ -649,7 +649,7 @@ typedef struct EEVEE_ObjectKey {
   /** Parent object for duplis */
   struct Object *parent;
   /** Dupli objects recursive unique identifier */
-  int id- [x]; /* MAX_DUPLI_RECUR */
+  int id[10]; /* MAX_DUPLI_RECUR */
 } EEVEE_ObjectKey;
 
 typedef struct EEVEE_ObjectMotionData {
diff --git a/source/blender/makesdna/DNA_object_types.h b/source/blender/makesdna/DNA_object_types.h
index 0250d853898..a92327a65b5 100644
--- a/source/blender/makesdna/DNA_object_types.h
+++ b/source/blender/makesdna/DNA_object_types.h
@@ -752,7 +752,7 @@ enum {
   OB_EMPTY_IMAGE_USE_ALPHA_BLEND = 1 << 0,
 };
 
-#define MAX_DUPLI_RECUR 8
+#define MAX_DUPLI_RECUR 10
 
 #ifdef __cplusplus
 }

This was touched before (but in another context:

A related issue came up before in #48913 (Viewport gets stuck when two group instances are emitted from one face using dupli-verts)
And it seems this was raised once in c0161a1bab.
But then reduced again in bfc644dcfb.

@mont29, @brecht: I guess this can/should be closed as Known Issue (as in: wont be fixed)?

Can confirm the behavior. This seems to be restricted by `MAX_DUPLI_RECUR`. Changing this might be possible (needs to be done in a couple of places, see the following patch), but I assume there will be issues with `persistent_id` then (that I cannot forsee). [P2350: T89844_snippet](https://archive.blender.org/developer/P2350.txt) ``` diff --git a/intern/cycles/blender/blender_id_map.h b/intern/cycles/blender/blender_id_map.h index 198cfb4b29a..aed18b44e21 100644 --- a/intern/cycles/blender/blender_id_map.h +++ b/intern/cycles/blender/blender_id_map.h @@ -196,7 +196,7 @@ template<typename K, typename T> class id_map { * To uniquely identify instances, we use the parent, object and persistent instance ID. * We also export separate object for a mesh and its particle hair. */ -enum { OBJECT_PERSISTENT_ID_SIZE = 8 /* MAX_DUPLI_RECUR in Blender. */ }; +enum { OBJECT_PERSISTENT_ID_SIZE = 10 /* MAX_DUPLI_RECUR in Blender. */ }; struct ObjectKey { void *parent; diff --git a/source/blender/blenkernel/BKE_duplilist.h b/source/blender/blenkernel/BKE_duplilist.h index c142d5338d1..d3e3ad9a0f1 100644 --- a/source/blender/blenkernel/BKE_duplilist.h +++ b/source/blender/blenkernel/BKE_duplilist.h @@ -51,7 +51,7 @@ typedef struct DupliObject { /* Persistent identifier for a dupli object, for inter-frame matching of * objects with motion blur, or inter-update matching for syncing. */ - int persistent_id- [x]; /* MAX_DUPLI_RECUR */ + int persistent_id[10]; /* MAX_DUPLI_RECUR */ /* Particle this dupli was generated from. */ struct ParticleSystem *particle_system; diff --git a/source/blender/draw/engines/eevee/eevee_private.h b/source/blender/draw/engines/eevee/eevee_private.h index f51b4fa0127..fe719084a61 100644 --- a/source/blender/draw/engines/eevee/eevee_private.h +++ b/source/blender/draw/engines/eevee/eevee_private.h @@ -649,7 +649,7 @@ typedef struct EEVEE_ObjectKey { /** Parent object for duplis */ struct Object *parent; /** Dupli objects recursive unique identifier */ - int id- [x]; /* MAX_DUPLI_RECUR */ + int id[10]; /* MAX_DUPLI_RECUR */ } EEVEE_ObjectKey; typedef struct EEVEE_ObjectMotionData { diff --git a/source/blender/makesdna/DNA_object_types.h b/source/blender/makesdna/DNA_object_types.h index 0250d853898..a92327a65b5 100644 --- a/source/blender/makesdna/DNA_object_types.h +++ b/source/blender/makesdna/DNA_object_types.h @@ -752,7 +752,7 @@ enum { OB_EMPTY_IMAGE_USE_ALPHA_BLEND = 1 << 0, }; -#define MAX_DUPLI_RECUR 8 +#define MAX_DUPLI_RECUR 10 #ifdef __cplusplus } ``` This was touched before (but in another context: --- A related issue came up before in #48913 (Viewport gets stuck when two group instances are emitted from one face using dupli-verts) And it seems this was raised once in c0161a1bab. But then reduced again in bfc644dcfb. --- @mont29, @brecht: I guess this can/should be closed as `Known Issue` (as in: wont be fixed)?

Philipp Oeser changed title from ~~Nesting Collection instances cause first objects to disappear~~ to Nesting Collection instances cause first objects to disappear (restricted by MAX_DUPLI_RECUR)

2021-08-30 13:56:14 +02:00

Bastien Montagne commented

2021-08-30 15:04:14 +02:00

Changed status from 'Needs Developer To Reproduce' to: 'Archived'

Bastien Montagne closed this issue

2021-08-30 15:04:14 +02:00

Bastien Montagne commented

2021-08-30 15:04:14 +02:00

Not sure about raising that level of nesting, to me it looks already fairly reasonable as it is, you can always build cases that will break any such limit anyway... Will let that decision to @brecht

In any case, definitely not a bug, not even a 'known issue', just an internal limitation (similar to max amount of materials, etc.).

Not sure about raising that level of nesting, to me it looks already fairly reasonable as it is, you can always build cases that will break any such limit anyway... Will let that decision to @brecht In any case, definitely not a bug, not even a 'known issue', just an internal limitation (similar to max amount of materials, etc.).

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Nesting Collection instances cause first objects to disappear (restricted by MAX_DUPLI_RECUR) #89844