M:3L Lab

M:3L research

3D Intelligence

M:3L develops geometric and spatial AI for zero-shot 3D grounding, open-vocabulary detection, scene layouts, and real-world understanding from point clouds or multi-view imagery.

Overview

The laboratory works with point clouds, multi-view images, and fully unposed RGB captures. Its systems reason over 3D scenes, object geometry, scene layouts, spatial relationships, open-vocabulary objects, and geometric representations.

M:3L researchers co-authored Z3D, Zoo3D, and TUN3D. These projects address complementary parts of scene-level 3D understanding: language-conditioned grounding, open-vocabulary object detection, and joint layout-plus-object understanding without requiring known camera poses or externally provided depth in the unposed-image setting.

The research supports a path from perception to structured engineering representations: images or point clouds can inform spatial understanding, geometric reconstruction, editable CAD, simulation-ready models, and downstream optimization.

Demonstrated M:3L research

  • Z3D: zero-shot 3D visual grounding from multi-view images, evaluated on ScanRefer and Nr3D.
  • Zoo3D: training-free and self-supervised open-vocabulary 3D object detection, evaluated on ScanNet and ARKitScenes.
  • TUN3D: joint scene-layout estimation and 3D object detection from point clouds, posed images, or fully unposed RGB imagery, evaluated on ScanNet, S3DIS, ARKitScenes, and Structured3D.

Technical capabilities

  • Zero-shot 3D visual grounding
  • Training-free open-vocabulary 3D object detection
  • Joint scene-layout estimation and 3D detection
  • Unposed multi-view image understanding
  • Point-cloud, posed-image, and unposed-image processing
  • Geometric reasoning and spatial relationships
  • Open-world and open-vocabulary perception

Z3D: Zero-Shot 3D Visual Grounding from Images

Z3D localizes the 3D object referred to by a natural-language query. It operates on multi-view imagery and can optionally use camera poses and depth maps, while its zero-shot formulation avoids task-specific geometric supervision and predefined object priors.

The method combines proposal generation, view selection, prompt-based segmentation, 2D-to-3D lifting, and multi-view aggregation. The associated paper reports state-of-the-art performance among zero-shot methods on ScanRefer and Nr3D at publication time.

  • Benchmarks: ScanRefer and Nr3D
  • Inputs: point clouds or multi-view images, with posed and unposed-image settings
  • Evidence: overall ScanRefer [email protected]/[email protected] of 54.2/46.0 in the zero-shot point-cloud setting; Nr3D overall top-1 accuracy of 54.8

Zoo3D: Zero-Shot 3D Object Detection at Scene Level

Zoo3D introduces a training-free route to scene-level 3D detection. It clusters 2D instance masks across views to construct class-agnostic 3D boxes, then assigns open-vocabulary labels using best-view selection and view-consensus visual-language matching.

Zoo3D0 is zero-shot and requires no training; Zoo3D1 trains a class-agnostic detector on pseudo-labels generated by Zoo3D0. The associated paper reports state-of-the-art open-vocabulary results across ScanNet-based and ARKitScenes evaluations at publication time.

  • Benchmarks: ScanNet20, ScanNet60, ScanNet200, and ARKitScenes
  • Inputs: point clouds, posed multi-view images, or unposed images
  • Evidence: ScanNet200 point-cloud [email protected]/[email protected] of 21.1/14.1 for Zoo3D0 and 23.5/15.2 for Zoo3D1

TUN3D: Towards Real-World Scene Understanding from Unposed Images

TUN3D jointly estimates room layouts and detects 3D objects. In its fully unposed setting, the input is an ordinary image collection without known camera intrinsics, extrinsics, ground-truth poses, or externally provided depth.

DUSt3R reconstructs geometry and camera parameters, while a lightweight sparse-convolutional model uses dedicated object-detection and parametric wall-layout heads. This formulation targets consumer-device capture and recorded imagery rather than depth-sensor-only acquisition.

  • Benchmarks: ScanNet, S3DIS, ARKitScenes, and Structured3D
  • Unposed ScanNet evidence: layout F1 46.5, detection [email protected] 44.0, and [email protected] 20.7
  • Relevant domains: robotics, architecture, building reconstruction, digital twins, embodied AI, and autonomous engineering

Research evidence and benchmarks

Z3D: Zero-Shot 3D Visual Grounding from Images

BenchmarkTaskInputMetricResultEvidence
ScanReferZero-shot 3D visual groundingGround-truth point cloud; no bounding-box or text supervisionOverall [email protected] / [email protected]54.2 / 46.0Z3D paper, Table 1
Reported as state of the art among zero-shot approaches in the associated paper.
ScanReferZero-shot 3D visual groundingPosed multi-view RGBOverall [email protected] / [email protected]42.8 / 24.8Z3D paper, Table 1
ScanReferZero-shot 3D visual groundingUnposed multi-view RGBOverall [email protected] / [email protected]31.2 / 12.9Z3D paper, Table 1
Nr3DZero-shot 3D visual groundingDepth-aware settingOverall top-1 accuracy54.8Z3D paper, Table 2
The strongest zero-shot result in the paper's main Nr3D table was 54.8 versus 54.3 for SPAZER.

Zoo3D: Zero-Shot 3D Object Detection at Scene Level

BenchmarkTaskInputMetricResultEvidence
ScanNet200Open-vocabulary 3D object detection (Zoo3D0)Point cloud and posed scene images; training-free[email protected] / [email protected]21.1 / 14.1Zoo3D paper, Table 2
ScanNet200Open-vocabulary 3D object detection (Zoo3D1)Point cloud and posed scene images; self-supervised pseudo-label training[email protected] / [email protected]23.5 / 15.2Zoo3D paper, Table 2
ScanNet200Open-vocabulary 3D object detection (Zoo3D0 / Zoo3D1)Fully unposed multi-view images[email protected] / [email protected]8.3 / 2.9 (Zoo3D0); 10.7 / 3.8 (Zoo3D1)Zoo3D paper, Table 2
ARKitScenesOpen-vocabulary 3D object detection (Zoo3D0 / Zoo3D1)Point cloud and posed images[email protected] / [email protected]24.4 / 11.0 (Zoo3D0); 34.2 / 24.2 (Zoo3D1)Zoo3D paper, Table 15
ARKitScenesOpen-vocabulary 3D object detection (Zoo3D0 / Zoo3D1)Unposed multi-view images[email protected] / [email protected]13.0 / 2.6 (Zoo3D0); 16.1 / 3.5 (Zoo3D1)Zoo3D paper, Table 15

TUN3D: Towards Real-World Scene Understanding from Unposed Images

BenchmarkTaskInputMetricResultEvidence
ScanNetJoint layout estimation and 3D object detectionUnposed multi-view RGB; no known poses or external depthLayout F1 / detection [email protected] / [email protected]46.5 / 44.0 / 20.7TUN3D paper, Table I
S3DISJoint layout estimation and 3D object detectionUnposed multi-view RGB; no known poses or external depthLayout F1 / detection [email protected] / [email protected]20.8 / 11.0 / 2.2TUN3D paper, Table I
ScanNetJoint layout estimation and 3D object detectionPosed multi-view RGB; no ground-truth depthLayout F1 / detection [email protected] / [email protected]55.2 / 57.4 / 35.6TUN3D paper, Table I
ARKitScenesLayout estimationGround-truth point cloud; cross-dataset evaluationLayout F130.3TUN3D paper, Table II
The paper reports 25.9 for Omni-PQ under the same table protocol.
Structured3DLayout estimation and 3D object detectionGround-truth point cloudLayout [email protected]/[email protected]; detection [email protected]/[email protected]90.5/89.6; 73.9/65.4TUN3D paper, Table III

Values are paper-reported results for the stated input and evaluation protocol. Potential applications are not deployment claims.

Research directions

  • Open-world spatial understanding without fixed object vocabularies
  • Pose-free and depth-free scene understanding from ordinary image capture
  • Geometric representations that connect perception with CAD and simulation
  • Efficient holistic models that jointly represent objects and room structure

Potential applications

  • Robotics and embodied AI
  • Architecture and building reconstruction
  • Digital twins and spatial agents
  • Construction and facility understanding
  • Reverse engineering and 3D asset extraction

These are relevant application domains, not claims that every application is deployed.

Related publications

ACL 2026 · A*-ranked conference

Z3D: Zero-Shot 3D Visual Grounding from Images

Nikita Drozdov, Andrey Lemeshko, Nikita Gavrilov, Anton Konushin, Danila Rukhovich, Maksim Kolodiazhnyi

A universal pipeline for localizing objects in 3D scenes from multi-view images using zero-shot methods, without geometric supervision or object priors.

Status: Accepted at ACL 2026

CVPR 2026 · A*-ranked conference

Zoo3D: Zero-Shot 3D Object Detection at Scene Level

Andrey Lemeshko, Bulat Gabdullin, Nikita Drozdov, Anton Konushin, Danila Rukhovich, Maksim Kolodiazhnyi

The first training-free 3D object detection framework. It constructs 3D bounding boxes through graph clustering of 2D instance masks and assigns open-vocabulary semantic labels.

Status: Accepted at CVPR 2026

Connected research

  • CAD Intelligence: M:3L develops multimodal systems that reconstruct structured, editable, executable engineering representations from point clouds, multi-view images, and text.
  • Agentic AI: M:3L develops autonomous, tool-using single-agent and multi-agent AI systems for scientific, engineering, and enterprise workflows.