The main weaknesses of this paper are the lack of enough qualitative results and the ambiguity of explanation.
1. In the ablation study of 4.3, only one particular qualitative example is shown to demonstrate the effectiveness of different components. This is far from being convincing. The authors should have included more than 10 results of different prompts in the appendix for that.
2. In the "bidirectional guidance" part of section 4.3 Ablation Studies, the results shown at the top row of figure 6 seem to be totally different shapes. I understand this can happen for the 2D diffusion model. However the text also says "... and the 3D diffusion model manifests anomalies in both texture and geometric constructs.". But where are the 3D diffusion results? From my understanding the results from the 3D diffusion model should always look like the same shape and yield consistent multi-view renderings. I did not find these results in figure 6.
3. Figure 4 shows the main qualitative results of the proposed feed-forward method. However there is no comparison to previous methods. I think at least the comparison to Shap-E should be included.
4. The results of Zero-1-to-3 shown in figure 5 are weird. Why all the others methods shown are the final 3D results with mesh visualization, but the Zero-1-to-3 only has multi-view generation results? My understanding is to generation the 3D results at the left lower corner of Figure 5, we still need to use the SDS loss. If this is true, then a directly competitor should be using Zero-1-to-3 with SDS loss.
5. More details about the decoupled geometry and texture control in page 8 are needed. What does it mean to fix the 3D prior? Do you mean fixing the initial noise of the 3D diffusion? When fixing the textual prompt if the 2D diffusion, do you also fix the initial noise?
2. In the "bidirectional guidance" part of section 4.3 Ablation Studies, the results shown at the top row of figure 6 seem to be totally different shapes. I understand this can happen for the 2D diffusion model. However the text also says "... and the 3D diffusion model manifests anomalies in both texture and geometric constructs.". But where are the 3D diffusion results? From my understanding the results from the 3D diffusion model should always look like the same shape and yield consistent multi-view renderings. I did not find these results in figure 6.