diff --git a/packages/shared/src/contracts/model3d/common/Model3dGenerationTargetRef.ts b/packages/shared/src/contracts/model3d/common/Model3dGenerationTargetRef.ts
index 21c0a11f0..36ca403fe 100644
--- a/packages/shared/src/contracts/model3d/common/Model3dGenerationTargetRef.ts
+++ b/packages/shared/src/contracts/model3d/common/Model3dGenerationTargetRef.ts
@@ -1,8 +1,18 @@
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
 
 /**
- * 结果落点引用：与请求 `target` 同分支，但给的是已创建资源 / 素材的正式 ID。
+ * 结果落点引用：与请求落点同形的平坦可选字段，给的是已创建资源 / 素材的正式 ID。
+ *
+ * 与其它生成工具一致，项目资源与素材库可以同时产出（前端画布链路两个都发），
+ * 因此两个 ID 都是可选的：哪个落点写了行就带哪个 ID，两个都写了就都带。
  */
-export type Model3dGenerationTargetRef =
-  | { kind: 'projectResource'; resourceId: string }
-  | { kind: 'assetLibrary'; assetId: string };
+export type Model3dGenerationTargetRef = {
+  /**
+   * 项目资源落点的正式资源 ID；没落画布时缺省。
+   */
+  resourceId?: string | null;
+  /**
+   * 素材库落点的正式素材 ID；没落素材库时缺省。
+   */
+  assetId?: string | null;
+};
diff --git a/server-rs/crates/api-server/src/tripo3d/job.rs b/server-rs/crates/api-server/src/tripo3d/job.rs
index f11582137..480e69589 100644
--- a/server-rs/crates/api-server/src/tripo3d/job.rs
+++ b/server-rs/crates/api-server/src/tripo3d/job.rs
@@ -102,9 +102,10 @@ impl Model3dJobRequest {
 
 const MODEL3D_IMAGE_TO_MODEL_AUDIT_PROMPT: &str = "图生 3D 模型";
 
-/// 结果落点：与其它生成接口同形的平坦字段（项目资源 / 素材库二选一）。
+/// 结果落点：与其它生成接口同形的平坦字段（项目资源 / 素材库可选，至少给一个）。
 ///
-/// 校验层保证「恰好给一个」，因此下游按 `project_id` 是否存在分辨落点，不再需要判别枚举。
+/// 与其它生成工具一致，两个落点可以同时给（前端画布链路两个都发），因此下游不再按
+/// 「二选一」分辨落点：`project_id` 有就落画布，`asset_folder_id` 有就落素材库。
 #[derive(Clone, Copy, Debug)]
 pub(crate) struct Model3dJobTarget<'a> {
     pub(crate) project_id: Option<&'a str>,
diff --git a/server-rs/crates/api-server/src/tripo3d/target.rs b/server-rs/crates/api-server/src/tripo3d/target.rs
index b4dc1d218..e4d2a3827 100644
--- a/server-rs/crates/api-server/src/tripo3d/target.rs
+++ b/server-rs/crates/api-server/src/tripo3d/target.rs
@@ -27,10 +27,11 @@ pub(crate) async fn preflight_generation_target(
     owner_user_id: &str,
     target: Model3dJobTarget<'_>,
 ) -> Result<(), AppError> {
-    let Some((field, project_id, asset_folder_id)) = preflight_target_locator(target) else {
-        // 校验层保证「恰好一个落点」，这里只是纵深防御：真走到这里也不能放行无落点提交。
+    let Some((project_id, asset_folder_id)) = preflight_target_locator(target) else {
+        // 校验层保证「至少一个落点」，这里只是纵深防御：真走到这里也不能放行无落点提交。
         return Err(target_unavailable("projectId"));
     };
+    let field = target_unavailable_field(project_id.as_deref(), asset_folder_id.as_deref());
     state
         .spacetime_client()
         .preflight_editor_generation_target(EditorGenerationTargetPreflightRecordInput {
@@ -44,22 +45,37 @@ pub(crate) async fn preflight_generation_target(
         .map_err(|error| collapse_target_unavailable(error, field))
 }
 
-/// 平坦落点 → 定点预检入参：返回（出错时点名的字段名、项目 ID、素材夹 ID）。
+/// 平坦落点 → 定点预检入参：返回（项目 ID、素材夹 ID）。
 ///
-/// 传下去的就是 trim 后的原值：校验值与随后入队、落库的值必须逐字一致，
+/// 与其它生成工具同一口径：两个落点可以同时给（前端画布链路两个都发），procedure 会逐个定点查；
+/// 传下去的就是 trim 后的原值 —— 校验值与随后入队、落库的值必须逐字一致，
 /// 不能校验归一化后的目录却把原始值落库。
 /// 返回 `None` 表示两个落点字段都没给：调用方按「落点不可用」拒绝。
 fn preflight_target_locator(
     target: Model3dJobTarget<'_>,
-) -> Option<(&'static str, Option<String>, Option<String>)> {
-    match (target.project_id, target.asset_folder_id) {
-        (Some(project_id), _) => Some(("projectId", Some(project_id.trim().to_string()), None)),
-        (None, Some(asset_folder_id)) => Some((
-            "assetFolderId",
-            None,
-            Some(asset_folder_id.trim().to_string()),
-        )),
-        (None, None) => None,
+) -> Option<(Option<String>, Option<String>)> {
+    let project_id = target
+        .project_id
+        .map(str::trim)
+        .filter(|value| !value.is_empty())
+        .map(str::to_string);
+    let asset_folder_id = target
+        .asset_folder_id
+        .map(str::trim)
+        .filter(|value| !value.is_empty())
+        .map(str::to_string);
+    (project_id.is_some() || asset_folder_id.is_some()).then_some((project_id, asset_folder_id))
+}
+
+/// 落点不可用时对外点名的字段：只给一个就点它，两个都给无法归因，回落到 `target`。
+fn target_unavailable_field(
+    project_id: Option<&str>,
+    asset_folder_id: Option<&str>,
+) -> &'static str {
+    match (project_id.is_some(), asset_folder_id.is_some()) {
+        (true, false) => "projectId",
+        (false, true) => "assetFolderId",
+        _ => "target",
     }
 }
 
@@ -118,7 +134,7 @@ mod tests {
         );
     }
 
-    /// 平坦落点收敛成定点预检入参：只做 trim，两个都不给返回 `None`。
+    /// 平坦落点收敛成定点预检入参：只做 trim，两个都给就都传，都不给返回 `None`。
     #[test]
     fn flat_locator_maps_to_point_lookup_without_rewriting_ids() {
         let locator = |project_id, asset_folder_id| {
@@ -132,17 +148,34 @@ mod tests {
 
         assert_eq!(
             locator(Some(" project-1 "), None),
-            Some(("projectId", Some("project-1".to_string()), None))
+            Some((Some("project-1".to_string()), None))
         );
         assert_eq!(
             locator(None, Some(" folder-1 ")),
-            Some(("assetFolderId", None, Some("folder-1".to_string())))
+            Some((None, Some("folder-1".to_string())))
         );
-        // 两个都给由校验层拒绝；预检的兜底口径是项目优先，不静默换成素材库。
         assert_eq!(
             locator(Some("project-1"), Some("folder-1")),
-            Some(("projectId", Some("project-1".to_string()), None))
+            Some((Some("project-1".to_string()), Some("folder-1".to_string())))
         );
         assert_eq!(locator(None, None), None);
     }
+
+    /// 出错字段：只有一个落点时点名它，两个都给时无法归因，回落到 `target`。
+    #[test]
+    fn unavailable_field_names_the_given_locators() {
+        assert_eq!(
+            target_unavailable_field(Some("project-1"), None),
+            "projectId"
+        );
+        assert_eq!(
+            target_unavailable_field(None, Some("folder-1")),
+            "assetFolderId"
+        );
+        assert_eq!(
+            target_unavailable_field(Some("project-1"), Some("folder-1")),
+            "target"
+        );
+        assert_eq!(target_unavailable_field(None, None), "target");
+    }
 }
diff --git a/server-rs/crates/api-server/src/tripo3d/validation.rs b/server-rs/crates/api-server/src/tripo3d/validation.rs
index bf0eadf62..1563d3d7d 100644
--- a/server-rs/crates/api-server/src/tripo3d/validation.rs
+++ b/server-rs/crates/api-server/src/tripo3d/validation.rs
@@ -356,16 +356,22 @@ mod tests {
         assert_eq!(error.field().as_deref(), Some("assetFolderId"));
     }
 
-    /// 平坦落点字段的四种组合：恰好一个才通过；都给、都不给与 blank 都按 400 拒绝。
+    /// 平坦落点的合法组合：项目、素材库都可以给，两个一起给也合法（与其它生成工具一致）；
+    /// 一个都不给、blank 与「素材库落点带画布占位框」都按 400 拒绝。
     #[test]
-    fn target_requires_exactly_one_flat_locator() {
-        let cases: [(&str, Value, Option<&str>); 6] = [
-            ("projectId", json!({ "projectId": "project-1" }), None),
+    fn target_accepts_both_locators_but_requires_at_least_one() {
+        let cases: [(&str, Value, Option<&str>); 7] = [
+            ("只给 projectId", json!({ "projectId": "project-1" }), None),
             (
-                "assetFolderId",
+                "只给 assetFolderId",
                 json!({ "assetFolderId": "folder-1" }),
                 None,
             ),
+            (
+                "两个都给",
+                json!({ "projectId": "project-1", "assetFolderId": "folder-1" }),
+                None,
+            ),
             (
                 "空白 projectId",
                 json!({ "projectId": "  " }),
@@ -376,12 +382,22 @@ mod tests {
                 json!({ "assetFolderId": " " }),
                 Some("assetFolderId"),
             ),
-            (
-                "两个都给",
-                json!({ "projectId": "project-1", "assetFolderId": "folder-1" }),
-                Some("assetFolderId"),
-            ),
             ("都不给", json!({}), Some("projectId")),
+            (
+                "素材库落点带画布占位框",
+                json!({
+                    "assetFolderId": "folder-1",
+                    "canvasCompletion": {
+                        "dialogId": "dialog-1",
+                        "title": "木椅",
+                        "placeholder": {
+                            "x": 1, "y": 2, "width": 3, "height": 4,
+                            "originalWidth": 3, "originalHeight": 4
+                        }
+                    }
+                }),
+                Some("canvasCompletion"),
+            ),
         ];
         for (name, target_fields, expected_field) in cases {
             let mut payload = json!({ "generation": generation_with(json!({})) });
@@ -449,24 +465,20 @@ fn validate_target(target: Model3dJobTarget<'_>) -> Result<(), Model3dRequestErr
             "素材库目录 ID 不能为空",
         ));
     }
-    match (project_id, asset_folder_id) {
-        (Some(_), Some(_)) => Err(Model3dRequestError::invalid(
-            "assetFolderId",
-            "项目资源与素材库落点只能给一个",
-        )),
-        (Some(_), None) => Ok(()),
-        (None, Some(_)) => {
-            if target.canvas_completion.is_some() {
-                return Err(Model3dRequestError::invalid(
-                    "canvasCompletion",
-                    "只有项目资源落点才能回填画布占位框",
-                ));
-            }
-            Ok(())
-        }
-        (None, None) => Err(Model3dRequestError::invalid(
+    // 与其它生成工具同一条口径：项目资源与素材库可以同时给（前端画布链路两个都发），
+    // 但一个都不给就没有结果落点——付费生成不能接受这种提交。
+    if project_id.is_none() && asset_folder_id.is_none() {
+        return Err(Model3dRequestError::invalid(
             "projectId",
             "必须给出落点：projectId（项目资源）或 assetFolderId（素材库）",
-        )),
+        ));
     }
+    // 画布占位框是项目资源落点的回填载荷：没有项目就没有画布可以回填。
+    if project_id.is_none() && target.canvas_completion.is_some() {
+        return Err(Model3dRequestError::invalid(
+            "canvasCompletion",
+            "只有项目资源落点才能回填画布占位框",
+        ));
+    }
+    Ok(())
 }
diff --git a/server-rs/crates/api-server/src/tripo3d/worker.rs b/server-rs/crates/api-server/src/tripo3d/worker.rs
index cfc930059..fd6adaa0f 100644
--- a/server-rs/crates/api-server/src/tripo3d/worker.rs
+++ b/server-rs/crates/api-server/src/tripo3d/worker.rs
@@ -239,7 +239,7 @@ async fn persist_result(
             "message": format!("落库 3D 生成结果时：{error}。"),
         }))
     })?;
-    // 落点与其它生成接口同形的平坦字段：校验层保证「项目资源 / 素材库恰好一个」。
+    // 落点与其它生成接口同形的平坦字段：校验层保证「至少一个」，两个都给时两条落点都写。
     let target = request.target();
     let project_id = target
         .project_id
@@ -272,8 +272,7 @@ async fn persist_result(
         MODEL3D_MODEL_SLOT,
     );
     let has_resource = project_id.is_some();
-    // 结果里回落的落点身份要在 project_id 被搬进资源记录之前留下。
-    let project_id_for_result = project_id.clone();
+    let has_asset = folder_id.is_some();
     let project_resource = project_id.map(|project_id| EditorProjectResourceCreateRecordInput {
         resource_id: resource_id.clone(),
         project_id,
@@ -329,9 +328,8 @@ async fn persist_result(
     let result = build_result(
         request.job_kind(),
         target_ref(
-            project_id_for_result.is_some(),
-            resource_id.clone(),
-            asset_id_for_result,
+            has_resource.then(|| resource_id.clone()),
+            has_asset.then_some(asset_id_for_result),
         ),
         &model,
         &preview,
@@ -387,16 +385,12 @@ async fn persist_result(
     Ok(())
 }
 
-/// 结果里的落点引用：项目落点回资源 ID，素材库落点回素材 ID。
-fn target_ref(
-    has_project: bool,
-    resource_id: String,
-    asset_id: String,
-) -> Model3dGenerationTargetRef {
-    if has_project {
-        Model3dGenerationTargetRef::ProjectResource { resource_id }
-    } else {
-        Model3dGenerationTargetRef::AssetLibrary { asset_id }
+/// 结果里的落点引用：写了项目资源行就带 `resourceId`，写了素材行就带 `assetId`；
+/// 两个落点都写（前端画布链路的常态）时两个都带 —— 与请求落点同形的平坦字段。
+fn target_ref(resource_id: Option<String>, asset_id: Option<String>) -> Model3dGenerationTargetRef {
+    Model3dGenerationTargetRef {
+        resource_id,
+        asset_id,
     }
 }
 
@@ -500,8 +494,9 @@ mod tests {
         ] {
             let result = build_result(
                 kind,
-                Model3dGenerationTargetRef::ProjectResource {
-                    resource_id: "resource-1".to_string(),
+                Model3dGenerationTargetRef {
+                    resource_id: Some("resource-1".to_string()),
+                    asset_id: None,
                 },
                 &model,
                 &preview,
@@ -510,8 +505,9 @@ mod tests {
             let result = &payload["result"];
 
             assert_eq!(result["kind"], json!(expected_kind));
-            assert_eq!(result["target"]["kind"], json!("projectResource"));
             assert_eq!(result["target"]["resourceId"], json!("resource-1"));
+            // 只落项目资源时不得凭空带出素材 ID：结果引用与请求落点同形。
+            assert_eq!(result["target"].get("assetId"), None);
             assert_eq!(
                 result["model"]["objectKey"],
                 json!("editor/model3d/task-1/model.glb")
diff --git a/server-rs/crates/shared-contracts/src/model3d/common/generation_target_ref.rs b/server-rs/crates/shared-contracts/src/model3d/common/generation_target_ref.rs
index 7b319e438..6dabe75f0 100644
--- a/server-rs/crates/shared-contracts/src/model3d/common/generation_target_ref.rs
+++ b/server-rs/crates/shared-contracts/src/model3d/common/generation_target_ref.rs
@@ -2,18 +2,21 @@ use serde::{Deserialize, Serialize};
 
 use super::MODEL3D_TS_EXPORT_DIR;
 
-/// 结果落点引用：与请求 `target` 同分支，但给的是已创建资源 / 素材的正式 ID。
-#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
-#[serde(tag = "kind", rename_all = "camelCase", deny_unknown_fields)]
+/// 结果落点引用：与请求落点同形的平坦可选字段，给的是已创建资源 / 素材的正式 ID。
+///
+/// 与其它生成工具一致，项目资源与素材库可以同时产出（前端画布链路两个都发），
+/// 因此两个 ID 都是可选的：哪个落点写了行就带哪个 ID，两个都写了就都带。
+#[derive(Clone, Debug, Default, Deserialize, Eq, PartialEq, Serialize)]
+#[serde(rename_all = "camelCase", deny_unknown_fields)]
 #[derive(ts_rs::TS)]
 #[ts(export, export_to = MODEL3D_TS_EXPORT_DIR)]
-pub enum Model3dGenerationTargetRef {
-    ProjectResource {
-        #[serde(rename = "resourceId")]
-        resource_id: String,
-    },
-    AssetLibrary {
-        #[serde(rename = "assetId")]
-        asset_id: String,
-    },
+pub struct Model3dGenerationTargetRef {
+    /// 项目资源落点的正式资源 ID；没落画布时缺省。
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    #[ts(optional = nullable)]
+    pub resource_id: Option<String>,
+    /// 素材库落点的正式素材 ID；没落素材库时缺省。
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    #[ts(optional = nullable)]
+    pub asset_id: Option<String>,
 }
diff --git a/server-rs/crates/shared-contracts/tests/model3d_api_request_contract.rs b/server-rs/crates/shared-contracts/tests/model3d_api_request_contract.rs
index a0b02ff08..3802c0cd5 100644
--- a/server-rs/crates/shared-contracts/tests/model3d_api_request_contract.rs
+++ b/server-rs/crates/shared-contracts/tests/model3d_api_request_contract.rs
@@ -114,7 +114,7 @@ fn api_request_rejects_unknown_top_level_fields() {
 fn generation_result_is_tagged_per_endpoint() {
     let result: Model3dGenerationResult = serde_json::from_value(json!({
         "kind": "textToModel",
-        "target": { "kind": "projectResource", "resourceId": "res-1" },
+        "target": { "resourceId": "res-1" },
         "model": {
             "objectKey": "models/res-1.glb",
             "contentType": "model/gltf-binary",
@@ -135,8 +135,9 @@ fn generation_result_is_tagged_per_endpoint() {
     };
     assert_eq!(
         text.target,
-        Model3dGenerationTargetRef::ProjectResource {
-            resource_id: "res-1".into()
+        Model3dGenerationTargetRef {
+            resource_id: Some("res-1".into()),
+            asset_id: None,
         }
     );
     assert_eq!(
@@ -161,7 +162,7 @@ fn generation_result_is_tagged_per_endpoint() {
     // 对称覆盖 imageToModel 分支：tag 路由与分支字段都要单独守住。
     let image_result: Model3dGenerationResult = serde_json::from_value(json!({
         "kind": "imageToModel",
-        "target": { "kind": "projectResource", "resourceId": "res-2" },
+        "target": { "assetId": "asset-2" },
         "model": {
             "objectKey": "models/res-2.glb",
             "contentType": "model/gltf-binary",
@@ -180,10 +181,12 @@ fn generation_result_is_tagged_per_endpoint() {
     let Model3dGenerationResult::ImageToModel(image) = image_result else {
         panic!("kind=imageToModel 不应解成 textToModel 分支");
     };
+    // 只落素材库时，平坦引用只带 assetId。
     assert_eq!(
         image.target,
-        Model3dGenerationTargetRef::ProjectResource {
-            resource_id: "res-2".into()
+        Model3dGenerationTargetRef {
+            resource_id: None,
+            asset_id: Some("asset-2".into()),
         }
     );
     assert_eq!(