diff --git a/docs/technical/【技术方案】Tripo 3D生成API集成-2026-09-21.md b/docs/technical/【技术方案】Tripo 3D生成API集成-2026-09-21.md
index ab8d116d3..128f99d70 100644
--- a/docs/technical/【技术方案】Tripo 3D生成API集成-2026-09-21.md	
+++ b/docs/technical/【技术方案】Tripo 3D生成API集成-2026-09-21.md	
@@ -161,7 +161,7 @@ thumbnailSrc  = 预览图
 width/height  = 预览图像素尺寸
 ```
 
-模型格式与体积由 `AssetObject` 承担（`content_type`、`content_length`、`content_hash`），因此不新增 `model_format`、`size_bytes`、`poly_count` 等列。两个槽位的 `content_type` 都在写入前按字节识别真实产物：模型按魔数认 GLB 的 `glTF` 头、FBX 的 `Kaydara FBX Binary` 头与 glTF 的 JSON 正文，预览按魔数认 PNG / JPEG / WebP；不直接采信 provider 返回或下载响应头声明的类型，对象键扩展名由该内容类型派生。只有字节判不出来时才回落到声明值（预览最终回落 `image/webp`）。客户端不复制这份格式清单：画布只按「`assetKind=model3d` 且 `objectKey` 非空」放行，能否交给 3D 查看器由 `packages/model3d-viewer` 判定，判据依次是读接口声明的 `Content-Type`、字节魔数、地址扩展名，全判不出来即按 `unsupported-format` 报错。
+模型格式与体积由 `AssetObject` 承担（`content_type`、`content_length`、`content_hash`），因此不新增 `model_format`、`size_bytes`、`poly_count` 等列。两个槽位的 `content_type` 都在写入前按字节识别真实产物：模型按魔数认 GLB 的 `glTF` 头、FBX 的 `Kaydara FBX Binary` 头与 glTF 的 JSON 正文，预览按魔数认 PNG / JPEG / WebP；不直接采信 provider 返回或下载响应头声明的类型，对象键扩展名由该内容类型派生。只有字节判不出来时才采信声明值，且声明值必须落在该槽位的白名单内（模型：`model/gltf-binary`、`model/gltf+json`、`model/fbx`、`application/x-fbx`；预览：`image/png`、`image/jpeg`、`image/jpg`、`image/webp`）；两边都对不上就直接按上游内容不合法失败并退款，不做任何兜底 —— 放行 `text/plain` 这类未知类型只会落成「错的 content type + 拼出来的扩展名」。客户端不复制这份格式清单：画布只按「`assetKind=model3d` 且 `objectKey` 非空」放行，能否交给 3D 查看器由 `packages/model3d-viewer` 判定，判据依次是读接口声明的 `Content-Type`、字节魔数、地址扩展名，全判不出来即按 `unsupported-format` 报错。
 
 `external_generation_job.phase` 的取值集合不变，仍只允许现有两种执行阶段；阶段文案由 api-server 映射，不扩展 schema 常量。
 
diff --git a/packages/shared/src/contracts/model3d/image-to-model/Model3dImageToModelRequest.ts b/packages/shared/src/contracts/model3d/image-to-model/Model3dImageToModelRequest.ts
index 15d1e671a..a5987a0f2 100644
--- a/packages/shared/src/contracts/model3d/image-to-model/Model3dImageToModelRequest.ts
+++ b/packages/shared/src/contracts/model3d/image-to-model/Model3dImageToModelRequest.ts
@@ -7,13 +7,13 @@ import type { Model3dImageToModelParams } from './Model3dImageToModelParams';
  * image-to-model API 请求：站内图片引用 + provider 生成参数 + 平台字段。
  *
  * 结果落点与 text-to-model 同形：平坦的可选 `projectId` / `canvasCompletion` /
- * `assetFolderId` / `assetLabel`，二选一，不用 tagged enum。
+ * `assetFolderId` / `assetLabel`，至少给一个，不用 tagged enum。
  */
 export type Model3dImageToModelRequest = {
   source: Model3dGenerationSource;
   generation: Model3dImageToModelParams;
   /**
-   * 项目资源落点；与 `assetFolderId` 二选一。
+   * 项目资源落点；与 `assetFolderId` 至少给一个，两个都给合法。
    */
   projectId?: string | null;
   /**
@@ -21,7 +21,7 @@ export type Model3dImageToModelRequest = {
    */
   canvasCompletion?: EditorCanvasGenerationCompletionPayload | null;
   /**
-   * 素材库落点；与 `projectId` 二选一。
+   * 素材库落点；与 `projectId` 至少给一个，两个都给合法。
    */
   assetFolderId?: string | null;
   /**
diff --git a/packages/shared/src/contracts/model3d/text-to-model/Model3dTextToModelRequest.ts b/packages/shared/src/contracts/model3d/text-to-model/Model3dTextToModelRequest.ts
index e37685d1a..26eda1340 100644
--- a/packages/shared/src/contracts/model3d/text-to-model/Model3dTextToModelRequest.ts
+++ b/packages/shared/src/contracts/model3d/text-to-model/Model3dTextToModelRequest.ts
@@ -10,12 +10,13 @@ import type { Model3dTextToModelParams } from './Model3dTextToModelParams';
  *
  * 结果落点与其它生成接口同形：平坦的可选 `projectId` / `canvasCompletion` /
  * `assetFolderId` / `assetLabel`，不用 tagged enum —— 客户端不必为「落项目还是落素材库」
- * 多拼一层判别结构。服务端按「二选一」校验：两个都给或都不给都拒绝。
+ * 多拼一层判别结构。服务端按「至少一个落点」校验：两个都不给拒绝，两个都给合法（两条落点都落）；
+ * 没有 `projectId` 时结果只落素材库，与其它画布生成工具一致。
  */
 export type Model3dTextToModelRequest = {
   generation: Model3dTextToModelParams;
   /**
-   * 项目资源落点；与 `assetFolderId` 二选一。
+   * 项目资源落点；与 `assetFolderId` 至少给一个，两个都给合法。
    */
   projectId?: string | null;
   /**
@@ -23,7 +24,7 @@ export type Model3dTextToModelRequest = {
    */
   canvasCompletion?: EditorCanvasGenerationCompletionPayload | null;
   /**
-   * 素材库落点；与 `projectId` 二选一。
+   * 素材库落点；与 `projectId` 至少给一个，两个都给合法。
    */
   assetFolderId?: string | null;
   /**
diff --git a/server-rs/crates/api-server/src/tripo3d/storage.rs b/server-rs/crates/api-server/src/tripo3d/storage.rs
index d50ffa118..98393d8a4 100644
--- a/server-rs/crates/api-server/src/tripo3d/storage.rs
+++ b/server-rs/crates/api-server/src/tripo3d/storage.rs
@@ -52,13 +52,36 @@ impl Model3dArtifactSlot {
         }
     }
 
-    /// provider 未给出可用 content type 时的兜底扩展名。
-    const fn fallback_extension(self) -> &'static str {
+    /// 本槽位接受的全部 content type。表外的取值一律拒绝：不做归一兜底，也不替
+    /// provider 猜一个类型，因为猜错的类型会连同扩展名一起写进 OSS metadata 与
+    /// `asset_object.content_type`，比失败更难发现。
+    const fn declared_content_types(self) -> &'static [&'static str] {
         match self {
-            Self::Model => "glb",
-            Self::Preview => "webp",
+            Self::Model => &[
+                "model/gltf-binary",
+                "model/gltf+json",
+                "model/fbx",
+                "application/x-fbx",
+            ],
+            Self::Preview => &["image/png", "image/jpeg", "image/jpg", "image/webp"],
         }
     }
+
+    /// 已知 content type 对应的对象键扩展名；表外返回 `None`。
+    fn artifact_extension(self, content_type: &str) -> Option<&'static str> {
+        if !self.declared_content_types().contains(&content_type) {
+            return None;
+        }
+        Some(match content_type {
+            "model/gltf-binary" => "glb",
+            "model/gltf+json" => "gltf",
+            "model/fbx" | "application/x-fbx" => "fbx",
+            "image/png" => "png",
+            "image/jpeg" | "image/jpg" => "jpg",
+            "image/webp" => "webp",
+            _ => return None,
+        })
+    }
 }
 
 /// 已落地的产物：对象键与对象元数据来自 HEAD 复核，不是 PUT 的入参原样回填。
@@ -89,13 +112,12 @@ pub(crate) async fn store_model3d_artifact(
         .oss_client()
         .ok_or_else(|| oss_unavailable("OSS 未完成环境变量配置，无法写入 3D 产物。"))?;
     let http_client = state.editor_oss_http_client();
-    let content_type = resolve_artifact_content_type(content_type, slot, bytes.as_slice());
+    let content_type = resolve_artifact_content_type(content_type, slot, bytes.as_slice())?;
     let sha256 = sha256_hex(bytes.as_slice());
-    let file_name = format!(
-        "{}.{}",
-        slot.file_stem(),
-        artifact_extension(content_type.as_str(), slot)
-    );
+    let extension = slot
+        .artifact_extension(content_type.as_str())
+        .ok_or_else(|| unsupported_artifact_content_type(content_type.as_str(), slot))?;
+    let file_name = format!("{}.{}", slot.file_stem(), extension);
     let put_result = oss_client
         .put_object(
             http_client,
@@ -167,20 +189,19 @@ pub(crate) async fn store_model3d_artifact(
     })
 }
 
-fn normalize_artifact_content_type(raw: &str, slot: Model3dArtifactSlot) -> String {
+/// provider 声明的 content type 去参数、去空白、转小写后与槽位白名单比对；
+/// 不在表里（含空值、`application/octet-stream`）返回 `None`。
+fn declared_artifact_content_type(raw: &str, slot: Model3dArtifactSlot) -> Option<&'static str> {
     let normalized = raw
         .split(';')
         .next()
         .map(str::trim)
         .unwrap_or_default()
         .to_ascii_lowercase();
-    if normalized.is_empty() || normalized == "application/octet-stream" {
-        return match slot {
-            Model3dArtifactSlot::Model => "model/gltf-binary".to_string(),
-            Model3dArtifactSlot::Preview => "image/webp".to_string(),
-        };
-    }
-    normalized
+    slot.declared_content_types()
+        .iter()
+        .copied()
+        .find(|known| *known == normalized)
 }
 
 /// glb 的容器魔数（小端 `glTF`）；`model/gltf+json` 的判据是首个非空白字节为 `{`。
@@ -225,43 +246,52 @@ fn sniff_preview_content_type(bytes: &[u8]) -> Option<&'static str> {
     }
 }
 
-/// 产物 content type：两个槽位都先嗅探字节，嗅不出来才信 provider 声明。
+/// 产物 content type：两个槽位都先嗅探字节，嗅不出来才信 provider 声明；两者都不成立就失败。
 ///
-/// provider 对二进制产物常给 `application/octet-stream`，归一后会被写成
-/// `model/gltf-binary` + `.glb`；客户端按这份 content type 判定能不能预览，说错就是
-/// 拿 GLTFLoader 去解 FBX。预览图同理：provider / CDN 常把 PNG 渲染图标成
-/// `application/octet-stream` 或干脆不写 `Content-Type`，照抄声明就会把 `image/webp`
-/// 写进 OSS metadata 与 `asset_object.content_type`，素材库下载命名与后台等非浏览器消费方
-/// 都会拿到错的类型。浏览器 `<img>` 自己能按魔数嗅探，但那不是让记录值继续说谎的理由。
+/// provider 对二进制产物常给 `application/octet-stream`，因此「字节优先」是这条链路的前提：
+/// 客户端按这份 content type 判定能不能预览，说错就是拿 GLTFLoader 去解 FBX。预览图同理：
+/// provider / CDN 常把 PNG 渲染图标成 `application/octet-stream` 或干脆不写 `Content-Type`，
+/// 照抄声明就会把 `image/webp` 写进 OSS metadata 与 `asset_object.content_type`，素材库下载
+/// 命名与后台等非浏览器消费方都会拿到错的类型。浏览器 `<img>` 自己能按魔数嗅探，
+/// 但那不是让记录值继续说谎的理由。
+///
+/// 声明值只在槽位白名单内才被采信：白名单外的取值会让类型与扩展名互相矛盾
+/// （provider 说 `text/plain`、对象键却只能拼出 `.glb`），并且把 provider 的任意文本
+/// 原样写进 OSS metadata 与 `asset_object.content_type`。字节认不出、声明也不在白名单
+/// 时直接失败，让一次生成失败退款，而不是落一条自相矛盾的元数据。
 ///
 /// 这里不把 worker 的 `preview_dimensions` 猜出的格式传下来：那一步是「必须能解码」的正交校验，
 /// 与写库时的类型归一各管一件事，重复的只是读文件头这一下，换来判定点只有一个。
-fn resolve_artifact_content_type(raw: &str, slot: Model3dArtifactSlot, bytes: &[u8]) -> String {
-    match slot {
-        Model3dArtifactSlot::Model => {
-            if let Some(sniffed) = sniff_model_content_type(bytes) {
-                return sniffed.to_string();
-            }
-        }
-        Model3dArtifactSlot::Preview => {
-            if let Some(sniffed) = sniff_preview_content_type(bytes) {
-                return sniffed.to_string();
-            }
-        }
+fn resolve_artifact_content_type(
+    raw: &str,
+    slot: Model3dArtifactSlot,
+    bytes: &[u8],
+) -> Result<String, AppError> {
+    let sniffed = match slot {
+        Model3dArtifactSlot::Model => sniff_model_content_type(bytes),
+        Model3dArtifactSlot::Preview => sniff_preview_content_type(bytes),
+    };
+    if let Some(sniffed) = sniffed {
+        return Ok(sniffed.to_string());
     }
-    normalize_artifact_content_type(raw, slot)
+    declared_artifact_content_type(raw, slot)
+        .map(str::to_string)
+        .ok_or_else(|| unsupported_artifact_content_type(raw, slot))
 }
 
-fn artifact_extension(content_type: &str, slot: Model3dArtifactSlot) -> &'static str {
-    match content_type {
-        "model/gltf-binary" => "glb",
-        "model/gltf+json" => "gltf",
-        "model/fbx" | "application/x-fbx" => "fbx",
-        "image/png" => "png",
-        "image/jpeg" | "image/jpg" => "jpg",
-        "image/webp" => "webp",
-        _ => slot.fallback_extension(),
-    }
+/// 声明类型不在槽位白名单里：不落库，也不猜一个类型继续走。
+fn unsupported_artifact_content_type(raw: &str, slot: Model3dArtifactSlot) -> AppError {
+    // 声明值是不可信输入，只回显截断后的一段，避免把任意长度的 provider 文本带进错误体。
+    let declared: String = raw.trim().chars().take(64).collect();
+    AppError::from_status(StatusCode::BAD_GATEWAY).with_details(json!({
+        "provider": TRIPO_PROVIDER,
+        "reason": "model3d-artifact-content-type-unsupported",
+        "message": format!(
+            "provider 返回的 {} 产物类型不可识别，且字节特征与任何受支持格式都不匹配。",
+            slot.file_stem()
+        ),
+        "declaredContentType": declared,
+    }))
 }
 
 fn sha256_hex(bytes: &[u8]) -> String {
@@ -282,19 +312,35 @@ mod tests {
     const JPEG_BYTES: &[u8] = b"\xFF\xD8\xFF\xE0rest-of-jpeg";
     const WEBP_BYTES: &[u8] = b"RIFF\x24\x00\x00\x00WEBPVP8 rest-of-webp";
 
+    /// 期望可归一的用例：失败即 panic，并把真实错误带出来。
+    fn resolve(declared: &str, slot: Model3dArtifactSlot, bytes: &[u8]) -> String {
+        resolve_artifact_content_type(declared, slot, bytes)
+            .unwrap_or_else(|error| panic!("声明 {declared} 的产物应当可归一：{error}"))
+    }
+
+    /// 期望被拒的用例：断言按「上游内容不合法」失败。
+    fn resolve_rejected(declared: &str, slot: Model3dArtifactSlot, bytes: &[u8]) {
+        let error = resolve_artifact_content_type(declared, slot, bytes)
+            .expect_err(&format!("声明 {declared} 的产物必须被拒绝"));
+        assert_eq!(
+            error.status_code(),
+            StatusCode::BAD_GATEWAY,
+            "声明 {declared} 的产物未通过识别时应按上游内容不合法失败"
+        );
+    }
+
     #[test]
     fn model_content_type_follows_bytes_over_declaration() {
-        // provider 对二进制产物常给 application/octet-stream。归一后是 model/gltf-binary，
-        // 一个 FBX 结果就会以 .glb 落库，客户端按它判定预览必然解析失败。
-        let content_type = resolve_artifact_content_type(
+        // provider 对二进制产物常给 application/octet-stream，照抄声明会让 FBX 以 .glb 落库。
+        let content_type = resolve(
             "application/octet-stream",
             Model3dArtifactSlot::Model,
             FBX_BYTES,
         );
         assert_eq!(content_type, "model/fbx");
         assert_eq!(
-            artifact_extension(content_type.as_str(), Model3dArtifactSlot::Model),
-            "fbx"
+            Model3dArtifactSlot::Model.artifact_extension(content_type.as_str()),
+            Some("fbx")
         );
     }
 
@@ -303,11 +349,7 @@ mod tests {
         // 声明说 glb、字节是 fbx 时以字节为准：这份 content type 会进 asset_object，
         // 前端拿它决定禁用 3D 预览与否，不能让它说错。
         assert_eq!(
-            resolve_artifact_content_type(
-                "model/gltf-binary",
-                Model3dArtifactSlot::Model,
-                FBX_BYTES,
-            ),
+            resolve("model/gltf-binary", Model3dArtifactSlot::Model, FBX_BYTES),
             "model/fbx"
         );
     }
@@ -315,49 +357,51 @@ mod tests {
     #[test]
     fn model_content_type_recognizes_each_supported_container() {
         assert_eq!(
-            resolve_artifact_content_type(
+            resolve(
                 "application/octet-stream",
                 Model3dArtifactSlot::Model,
-                GLB_BYTES,
+                GLB_BYTES
             ),
             "model/gltf-binary"
         );
         assert_eq!(
-            resolve_artifact_content_type(
+            resolve(
                 "application/octet-stream",
                 Model3dArtifactSlot::Model,
-                GLTF_JSON_BYTES,
+                GLTF_JSON_BYTES
             ),
             "model/gltf+json"
         );
         assert_eq!(
-            artifact_extension("model/gltf+json", Model3dArtifactSlot::Model),
-            "gltf"
+            Model3dArtifactSlot::Model.artifact_extension("model/gltf+json"),
+            Some("gltf")
         );
     }
 
     #[test]
-    fn model_content_type_keeps_declaration_when_bytes_are_unknown() {
-        // 嗅不出来时保持既有行为：声明可用就信声明，否则回落 glb。
+    fn model_content_type_rejects_declarations_outside_the_allowlist() {
+        // 字节认不出、声明又不在白名单时不再兜底成 .glb：放行 text/html 这类类型
+        // 会落成「错的 content type + 拼出来的扩展名」，比直接失败更难发现。
+        for declared in [
+            "application/octet-stream",
+            "text/html; charset=utf-8",
+            "text/plain",
+            "",
+        ] {
+            resolve_rejected(declared, Model3dArtifactSlot::Model, UNKNOWN_BYTES);
+        }
+        // 白名单内的声明在字节认不出时仍被采信，且扩展名与它一致。
         assert_eq!(
-            resolve_artifact_content_type(
-                "application/octet-stream",
-                Model3dArtifactSlot::Model,
-                UNKNOWN_BYTES,
-            ),
-            "model/gltf-binary"
-        );
-        assert_eq!(
-            resolve_artifact_content_type(
+            resolve(
                 "model/gltf-binary",
                 Model3dArtifactSlot::Model,
-                UNKNOWN_BYTES,
+                UNKNOWN_BYTES
             ),
             "model/gltf-binary"
         );
         assert_eq!(
-            artifact_extension("binary/octet-stream", Model3dArtifactSlot::Model),
-            "glb"
+            Model3dArtifactSlot::Model.artifact_extension("binary/octet-stream"),
+            None
         );
     }
 
@@ -373,57 +417,59 @@ mod tests {
             (WEBP_BYTES, "application/octet-stream", "image/webp"),
         ] {
             assert_eq!(
-                resolve_artifact_content_type(declared, Model3dArtifactSlot::Preview, bytes),
+                resolve(declared, Model3dArtifactSlot::Preview, bytes),
                 expected,
                 "声明 {declared} 的预览图必须按字节判定"
             );
         }
         // 类型与对象键扩展名同源于这一次判定：PNG 预览落库是 preview.png。
         assert_eq!(
-            artifact_extension("image/png", Model3dArtifactSlot::Preview),
-            "png"
+            Model3dArtifactSlot::Preview.artifact_extension("image/png"),
+            Some("png")
         );
     }
 
     #[test]
-    fn preview_content_type_keeps_declaration_when_bytes_are_unknown() {
-        // 嗅不出图片格式时保持既有行为：声明可用就信声明，否则回落 webp。
+    fn preview_content_type_keeps_only_allowlisted_declarations() {
+        // 带参数的声明先去掉参数再比对。
         assert_eq!(
-            resolve_artifact_content_type(
+            resolve(
                 "image/jpeg; charset=binary",
                 Model3dArtifactSlot::Preview,
-                UNKNOWN_BYTES,
+                UNKNOWN_BYTES
             ),
             "image/jpeg"
         );
-        assert_eq!(
-            resolve_artifact_content_type(
-                "application/octet-stream",
-                Model3dArtifactSlot::Preview,
-                UNKNOWN_BYTES,
-            ),
-            "image/webp"
+        // octet-stream、模型字节与白名单外的图片格式都不构成可用声明：
+        // 预览槽位同样不做「猜一个 webp」的兜底。
+        resolve_rejected(
+            "application/octet-stream",
+            Model3dArtifactSlot::Preview,
+            UNKNOWN_BYTES,
         );
-        // 模型字节不是预览图格式，不参与预览判定，仍走图片归一。
-        assert_eq!(
-            resolve_artifact_content_type(
-                "application/octet-stream",
-                Model3dArtifactSlot::Preview,
-                GLB_BYTES,
-            ),
-            "image/webp"
+        resolve_rejected(
+            "application/octet-stream",
+            Model3dArtifactSlot::Preview,
+            GLB_BYTES,
         );
+        resolve_rejected("image/avif", Model3dArtifactSlot::Preview, UNKNOWN_BYTES);
     }
 
     #[test]
-    fn artifact_extension_maps_known_fbx_spellings() {
+    fn artifact_extension_rejects_cross_slot_types() {
         assert_eq!(
-            artifact_extension("application/x-fbx", Model3dArtifactSlot::Model),
-            "fbx"
+            Model3dArtifactSlot::Model.artifact_extension("application/x-fbx"),
+            Some("fbx")
         );
         assert_eq!(
-            artifact_extension("image/png", Model3dArtifactSlot::Preview),
-            "png"
+            Model3dArtifactSlot::Model.artifact_extension("image/png"),
+            None,
+            "预览图类型不能落进模型槽位"
+        );
+        assert_eq!(
+            Model3dArtifactSlot::Preview.artifact_extension("model/fbx"),
+            None,
+            "模型类型不能落进预览槽位"
         );
     }
 }
diff --git a/server-rs/crates/shared-contracts/src/model3d/image_to_model/request.rs b/server-rs/crates/shared-contracts/src/model3d/image_to_model/request.rs
index b92372bf6..473af1895 100644
--- a/server-rs/crates/shared-contracts/src/model3d/image_to_model/request.rs
+++ b/server-rs/crates/shared-contracts/src/model3d/image_to_model/request.rs
@@ -8,7 +8,7 @@ use crate::model3d::common::Model3dGenerationSource;
 /// image-to-model API 请求：站内图片引用 + provider 生成参数 + 平台字段。
 ///
 /// 结果落点与 text-to-model 同形：平坦的可选 `projectId` / `canvasCompletion` /
-/// `assetFolderId` / `assetLabel`，二选一，不用 tagged enum。
+/// `assetFolderId` / `assetLabel`，至少给一个，不用 tagged enum。
 #[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 #[derive(ts_rs::TS)]
@@ -16,7 +16,7 @@ use crate::model3d::common::Model3dGenerationSource;
 pub struct Model3dImageToModelRequest {
     pub source: Model3dGenerationSource,
     pub generation: Model3dImageToModelParams,
-    /// 项目资源落点；与 `assetFolderId` 二选一。
+    /// 项目资源落点；与 `assetFolderId` 至少给一个，两个都给合法。
     #[serde(default, skip_serializing_if = "Option::is_none")]
     #[ts(optional = nullable)]
     pub project_id: Option<String>,
@@ -24,7 +24,7 @@ pub struct Model3dImageToModelRequest {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     #[ts(optional = nullable)]
     pub canvas_completion: Option<EditorCanvasGenerationCompletionPayload>,
-    /// 素材库落点；与 `projectId` 二选一。
+    /// 素材库落点；与 `projectId` 至少给一个，两个都给合法。
     #[serde(default, skip_serializing_if = "Option::is_none")]
     #[ts(optional = nullable)]
     pub asset_folder_id: Option<String>,
diff --git a/server-rs/crates/shared-contracts/src/model3d/text_to_model/request.rs b/server-rs/crates/shared-contracts/src/model3d/text_to_model/request.rs
index 99c4c79b9..14ab253c6 100644
--- a/server-rs/crates/shared-contracts/src/model3d/text_to_model/request.rs
+++ b/server-rs/crates/shared-contracts/src/model3d/text_to_model/request.rs
@@ -11,14 +11,15 @@ use crate::editor_canvas::EditorCanvasGenerationCompletionPayload;
 ///
 /// 结果落点与其它生成接口同形：平坦的可选 `projectId` / `canvasCompletion` /
 /// `assetFolderId` / `assetLabel`，不用 tagged enum —— 客户端不必为「落项目还是落素材库」
-/// 多拼一层判别结构。服务端按「二选一」校验：两个都给或都不给都拒绝。
+/// 多拼一层判别结构。服务端按「至少一个落点」校验：两个都不给拒绝，两个都给合法（两条落点都落）；
+/// 没有 `projectId` 时结果只落素材库，与其它画布生成工具一致。
 #[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 #[derive(ts_rs::TS)]
 #[ts(export, export_to = MODEL3D_TS_EXPORT_DIR)]
 pub struct Model3dTextToModelRequest {
     pub generation: Model3dTextToModelParams,
-    /// 项目资源落点；与 `assetFolderId` 二选一。
+    /// 项目资源落点；与 `assetFolderId` 至少给一个，两个都给合法。
     #[serde(default, skip_serializing_if = "Option::is_none")]
     #[ts(optional = nullable)]
     pub project_id: Option<String>,
@@ -26,7 +27,7 @@ pub struct Model3dTextToModelRequest {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     #[ts(optional = nullable)]
     pub canvas_completion: Option<EditorCanvasGenerationCompletionPayload>,
-    /// 素材库落点；与 `projectId` 二选一。
+    /// 素材库落点；与 `projectId` 至少给一个，两个都给合法。
     #[serde(default, skip_serializing_if = "Option::is_none")]
     #[ts(optional = nullable)]
     pub asset_folder_id: Option<String>,
diff --git a/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.test.ts b/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.test.ts
index 9f526ff80..7e7d00450 100644
--- a/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.test.ts
+++ b/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.test.ts
@@ -14,7 +14,7 @@ import {
   MODEL3D_GENERATION_FAILURE_MESSAGE,
   MODEL3D_GENERATION_TIMEOUT_MESSAGE,
   MODEL3D_IMAGE_SOURCE_REQUIRED_MESSAGE,
-  MODEL3D_PROJECT_REQUIRED_MESSAGE,
+  MODEL3D_TARGET_REQUIRED_MESSAGE,
   MODEL3D_TEXT_PROMPT_REQUIRED_MESSAGE,
   resolveModel3dGenerationErrorMessage,
   resolveModel3dImageSource,
@@ -175,6 +175,26 @@ describe('buildModel3dSubmissionPlan', () => {
     });
   });
 
+  it('没有画布工程时只给素材夹：不带 projectId，也不带 canvasCompletion', () => {
+    const result = buildModel3dSubmissionPlan({
+      dialog: createDialog('model3d-text-to-model', { prompt: '木椅' }),
+      projectId: '   ',
+      canvasCompletion: CANVAS_COMPLETION,
+      assetFolderId: 'project',
+      pricing: PRICING,
+    });
+    expect(result.ok).toBe(true);
+    if (!result.ok) {
+      return;
+    }
+    expect(result.plan.body).not.toHaveProperty('projectId');
+    expect(result.plan.body).not.toHaveProperty('canvasCompletion');
+    expect(result.plan.body).toMatchObject({
+      assetFolderId: 'project',
+      assetLabel: '木椅',
+    });
+  });
+
   it('素材夹落点只 trim，素材名缺省回落本次结果标题', () => {
     const result = buildModel3dSubmissionPlan({
       dialog: createDialog('model3d-text-to-model', { prompt: '木椅' }),
@@ -227,15 +247,16 @@ describe('buildModel3dSubmissionPlan', () => {
     ).not.toHaveProperty('textureQuality');
   });
 
-  it('缺工程、缺输入、缺定价都不组装请求', () => {
+  it('缺落点、缺输入、缺定价都不组装请求', () => {
     const textDialog = createDialog('model3d-text-to-model');
     expect(
       buildModel3dSubmissionPlan({
         dialog: { ...textDialog, prompt: '木椅' },
         projectId: '   ',
+        assetFolderId: '   ',
         pricing: PRICING,
       }),
-    ).toEqual({ ok: false, message: MODEL3D_PROJECT_REQUIRED_MESSAGE });
+    ).toEqual({ ok: false, message: MODEL3D_TARGET_REQUIRED_MESSAGE });
     expect(
       buildModel3dSubmissionPlan({
         dialog: textDialog,
diff --git a/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.ts b/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.ts
index be9a05a24..ea175aba4 100644
--- a/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.ts
+++ b/src/components/image-editor/model3d-generation/Model3dGenerationSubmission.ts
@@ -25,8 +25,8 @@ import {
 export const MODEL3D_TEXT_PROMPT_REQUIRED_MESSAGE = '请填写 3D 模型描述';
 export const MODEL3D_IMAGE_SOURCE_REQUIRED_MESSAGE =
   '请先选择一张画布图片或素材库图片';
-export const MODEL3D_PROJECT_REQUIRED_MESSAGE =
-  '请先保存当前画布工程，再生成 3D 模型';
+export const MODEL3D_TARGET_REQUIRED_MESSAGE =
+  '请先保存当前画布工程或打开素材库，再生成 3D 模型';
 export const MODEL3D_GENERATION_FAILURE_MESSAGE =
   '生成 3D 模型失败，请稍后重试。';
 export const MODEL3D_GENERATION_TIMEOUT_MESSAGE =
@@ -92,7 +92,7 @@ export function buildModel3dSubmissionPlan({
   canvasCompletion?: EditorCanvasGenerationCompletionInput | null;
   /**
    * 素材库落点：与其它画布生成工具一样，画布链路会把当前素材夹一起发出去，
-   * 结果因此同时落画布与素材库。缺省或空串表示本次不落素材库。
+   * 结果因此同时落画布与素材库；没有画布工程时它是唯一落点。缺省或空串表示本次不落素材库。
    */
   assetFolderId?: string | null;
   /** 素材库里的展示名；缺省用本次结果的标题。 */
@@ -102,9 +102,12 @@ export function buildModel3dSubmissionPlan({
   if (!isModel3dGenerationMode(dialog.mode)) {
     return { ok: false, message: MODEL3D_MODE_UNSUPPORTED_REASON };
   }
+  // 与其它画布生成工具同一条门禁：落点至少给一个（画布工程或素材夹）。
+  // 没有画布工程时仍然可以生成，结果只落素材库 —— 3D 不再要求「必须先保存工程」。
   const trimmedProjectId = projectId?.trim();
-  if (!trimmedProjectId) {
-    return { ok: false, message: MODEL3D_PROJECT_REQUIRED_MESSAGE };
+  const trimmedAssetFolderId = assetFolderId?.trim();
+  if (!trimmedProjectId && !trimmedAssetFolderId) {
+    return { ok: false, message: MODEL3D_TARGET_REQUIRED_MESSAGE };
   }
   const quote = resolveModel3dGenerationQuote(dialog, pricing);
   if (!quote.ok) {
@@ -138,16 +141,16 @@ export function buildModel3dSubmissionPlan({
   // 服务端按「至少一个落点」校验，项目资源与素材库可以同时给 —— 其它画布生成工具
   // 就是「projectId + assetFolderId + assetLabel」一起发，结果两边都落；3D 跟随同一口径，
   // 否则同一张画布生成出来的东西，只有 3D 不会出现在素材库。
-  const trimmedAssetFolderId = assetFolderId?.trim();
   const placement = {
-    projectId: trimmedProjectId,
+    ...(trimmedProjectId ? { projectId: trimmedProjectId } : {}),
     ...(trimmedAssetFolderId
       ? {
           assetFolderId: trimmedAssetFolderId,
           assetLabel: assetLabel?.trim() || resolveModel3dResultTitle(dialog),
         }
       : {}),
-    ...(canvasCompletion ? { canvasCompletion } : {}),
+    // 画布占位框是项目资源落点的回填载荷：没有工程就没有画布可以回填。
+    ...(trimmedProjectId && canvasCompletion ? { canvasCompletion } : {}),
   };
   const finish = (
     body: Model3dTextToModelRequest | Model3dImageToModelRequest,
diff --git a/src/components/image-editor/model3d-generation/useModel3dGenerationTask.test.tsx b/src/components/image-editor/model3d-generation/useModel3dGenerationTask.test.tsx
index c06838063..2dc5d1029 100644
--- a/src/components/image-editor/model3d-generation/useModel3dGenerationTask.test.tsx
+++ b/src/components/image-editor/model3d-generation/useModel3dGenerationTask.test.tsx
@@ -284,7 +284,7 @@ describe('useModel3dGenerationTask', () => {
     );
   });
 
-  it('画布工程还没保存时不发请求', async () => {
+  it('没有任何落点（既没有工程也没有素材夹）时不发请求', async () => {
     const { result } = renderTask({ dialog: createDialog(), projectId: null });
 
     await act(async () => {
@@ -296,6 +296,31 @@ describe('useModel3dGenerationTask', () => {
     expect(result.current.dialog.errorMessage).toContain('保存当前画布工程');
   });
 
+  it('没有画布工程时照样提交：只发素材夹，不发 projectId 与 canvasCompletion', async () => {
+    const submitResponse: Model3dGenerationSubmissionResponse = {
+      operationId: 'task-2',
+      jobKind: 'model3d_text_to_model',
+      status: QUEUED_STATUS,
+      statusUrl: '/api/runtime/external-generation/jobs/task-2',
+    };
+    submitModel3dGenerationRequestMock.mockResolvedValue(submitResponse);
+    const { result } = renderTask({
+      dialog: createDialog(),
+      projectId: null,
+      assetFolderId: 'project',
+    });
+
+    await act(async () => {
+      await result.current.submitModel3dGeneration(createDialog());
+    });
+
+    expect(submitModel3dGenerationRequestMock).toHaveBeenCalledTimes(1);
+    const request = submitModel3dGenerationRequestMock.mock.calls[0][0];
+    expect(request.body).not.toHaveProperty('projectId');
+    expect(request.body).not.toHaveProperty('canvasCompletion');
+    expect(request.body).toMatchObject({ assetFolderId: 'project' });
+  });
+
   it('非 3D 对话框不做任何事', async () => {
     const { result } = renderTask({
       dialog: createDialog({ mode: 'generate' }),