Why MLLMs Struggle to Determine Object Orientations
Organizations: Department of Computer Science, Colorado State University, Fort Collins, CO, USA
Abstract
Multimodal Large Language Models (MLLMs) struggle with tasks that require reasoning about 2D object orientation in images, as documented in prior work. Tong et al. and Nichols et al. hypothesize that these failures originate in the visual encoder, since commonly used encoders such as CLIP and SigLIP are trained for image-text semantic alignment rather than geometric reasoning. We design a controlled empirical protocol to test this claim by measuring whether rotations can be recovered from encoder representations. In particular, we examine SigLIP and ViT features from LLaVA OneVision and Qwen2.5-VL-7B-Instruct models, respectively, using full images, and examine CLIP representations in LLaVA 1.5 and 1.6 using rotated foreground patches against natural background images. Our null hypothesis is that orientation information is not preserved in the encoder embeddings and we test this by training linear regressors to predict object orientation from encoded features. Contrary to the hypothesis, we find that orientation information is recoverable from encoder representations: simple linear models accurately predict object orientations from embeddings. This contradicts the assumption that MLLM orientation failures originate in the visual encoder. Having rejected the accepted hypothesis that MLLMs struggle with 2D orientation tasks because of visual encoder limitations, we still don't know why they fail. Although a full explanation is beyond the scope of this paper, we show that although present, orientation information is spread diffusely across tens of thousands of features. This may or may not be while MLLMs fail to exploit the available orientation information.
Figures & tables
| Image Set | Prompt |
| Whole Images | How much is the 2nd image rotated clockwise when compared to the first image? |
| In-Place Rotated Images | How much is the object(s) rotated clockwise in degrees when compared to the first image? |
| dog on beach | By how much is the dog in the center inside the circle rotated if it is known that the rotation is zero degrees when the dog’s legs are vertical? |
| lizard on fish | By how much is the lizard in the center inside the circle rotated if it is known that the rotation is zero degrees when the lizard is roughly horizontal with its tail pointing left and its head pointing right? |
| train on indoor | By how much is the train in the center inside the circle rotated if it is known that the rotation is zero degrees when the train is vertical with the train tracks at the bottom and the steam from the train going vertically upwards? |
| Two Image Version Whole Images LLaVA-OV Qwen Instruct MAE Max Min MAE Max Min Dog 0.67 1.61 0.03 1.30 4.63 0.09 Lizard 0.44 1.63 0.01 2.20 6.31 0.06 Train 0.56 2.18 .01 2.43 10.01 0.29 Beach 0.74 2.67 0.03 1.63 4.98 0.03 Indoor 0.81 2.92 0.003 1.32 4.96 0.01 Fish 2.31 5.31 0.12 2.85 8.62 0.17 In-Place Rotated Object(s) Koala 0.36 1.47 0.01 1.01 3.66 0.06 Vase 0.48 1.76 0.003 0.90 4.18 0.01 Vase & Toaster 0.65 1.88 0.02 1.58 5.81 0.02 | Single Image Version Blended Images LLaVA 1.5 LLaVA 1.6 MAE Max Min MAE Max Min Dog Scale 1 1.41 4.19 0.06 0.62 2.40 0.001 Scale 2 0.89 3.20 0.0001 0.6 2.01 0.01 Scale 3 0.67 2.52 0.02 0.52 2.2 0.03 Train Scale 1 1.3 3.79 0.02 0.78 2.12 0.02 Scale 2 0.9 2.69 0.003 0.53 1.72 0.0002 Scale 3 0.72 2.12 0.008 0.42 1.2 0.005 Lizard Scale 1 2.08 7.24 0.0003 0.87 3.15 0.04 Scale 2 1.25 4.67 0.005 0.64 2.42 0.02 Scale 3 1.13 3.53 0.04 0.71 1.69 0.05 |
| Two Image Version Whole Images LLaVA-OV Qwen Instruct K-S p-value K-S p-value Dog 0.11 0.69 0.12 0.6 Lizard 0.14 0.43 0.09 0.9 Train 0.11 0.74 0.11 0.7 Beach 0.14 0.44 0.11 0.78 Indoor 0.09 0.87 0.09 0.89 Fish 0.06 0.997 0.12 0.62 In-Place Rotated Object(s) Koala 0.08 0.94 0.12 0.61 Vase 0.08 0.97 0.16 0.32 Vase & Toaster 0.09 0.93 0.09 0.9 | Single Image Version Blended Images LLaVA 1.5 LLaVA 1.6 K-S p-value K-S p-value Dog Scale 1 0.09 0.51 0.05 0.99 Scale 2 0.07 0.81 0.08 0.7 Scale 3 0.1 0.46 0.12 0.37 Train Scale 1 0.06 0.95 0.06 095 Scale 2 0.07 0.9 0.09 0.56 Scale 3 0.08 0.75 0.1 0.41 Lizard Scale 1 0.06 0.96 0.08 0.74 Scale 2 0.08 0.68 0.04 1 Scale 3 0.06 0.95 0.08 0.69 |
| LLaVA OneVision | Qwen2.5-VL-7B-Instruct | ||
| Angle ( ∘ ) | Count | Angle ( ∘ ) | Count |
| 90 | 149 | 90 | 142 |
| 180 | 28 | 10-15 | 14 |
| 0 | 2 | 10 | 11 |
| 45 | 1 | 180 | 6 |
| LLaVA 1.5 | LLaVA 1.6 | ||
| Angle ( ∘ ) | Count | Angle ( ∘ ) | Count |
| 90 | 25 | 90 | 40 |
| not possible | 10 | not possible | 17 |
| 45 | 9 | 0 | 6 |
| 0 | 8 | no answer | 4 |
| no answer | 4 | 180 | 2 |
| S/N | Train Set | Test set | MAE (degrees) | |
| LLaVA 1.5 | LLaVA 1.6 | |||
| 1 | dog on chessboard (FG rotated) | baseline (FG rotated) | 1.1 | 0.71 |
| BG + FG rotated | 96.5 | 92.34 | ||
| BG rotated | 80.09 | 80.48 | ||
| dog on grid (FG rotated) | baseline (FG rotated) | 1.28 | 0.68 | |
| BG + FG rotated | 92.13 | 88.14 | ||
| S/N | Train Set | Test set | MAE (degrees) | |
| LLaVA 1.5 | LLaVA 1.6 | |||
| 1 | lizard on chessboard (FG rotated) | baseline (FG rotated) | 1.81 | 1.36 |
| BG + FG rotated | 85.2 | 85.55 | ||
| BG rotated | 80.2 | 79.93 | ||
| lizard on grid (FG rotated) | baseline (FG rotated) | 1.87 | 1.16 | |
| BG + FG rotated | 84.1 | 87.22 | ||
| S/N | Train Set | Test set | MAE (degrees) | |
| LLaVA 1.5 | LLaVA 1.6 | |||
| 1 | train on chessboard (FG rotated) | baseline (FG rotated) | 1.2 | 0.77 |
| BG + FG rotated | 86.59 | 82.96 | ||
| BG rotated | 80.46 | 81 | ||
| train on grid (FG rotated) | baseline (FG rotated) | 1.3 | 0.94 | |
| BG + FG rotated | 87.4 | 87.96 | ||