# Realistic Simulation of Dissolution Process on Rock Surface
## 6 Discussion  
We presented a dissolution simulation framework for rock surfaces. By simplifying the process of dissolution in nature, we chose the movement trajectory of raindrops as the main simulation parameter. We introduced formulas of geology to account for simulating the splashing dissolution, dissolution under different conditions, deposition, and evaporation phenomena. Users can interactively set parameters related to rainfall, terrain height fields, rock solubility, and rock fissures to generate custom dissolution effects. The algorithm performs well in simulating the dissolution effect under different conditions, has good visual fidelity, and can achieve an interactive simulation efficiency.  
There are many possible avenues for future works. We presented a general solution, but we only experimented with dissolution rates to represent different rock properties and environmental factors. One important future direction is an extension to a representation of full rock properties, which would allow for accurate simulations. Another possible future aim would be to focus on a better method for constructing internal cave structures formed by the dissolution of underground rivers inside rocks. We may use the volume model to represent terrain information, so that it can support the carving operation of caves and ditches in rocks. In addition, a change in a rock's height may lead to the destruction of its stability, and then it may collapse. We also want to consider the collapse phenomenon of rock surfaces in a simulation process, which may be one of our research directions in the future.  
\begin{table}
\begin{tabular}{l|c c c c} Grid Rain & **5000** & **10,000** & **20,000** & **50,000** \\ \hline
10,000 & 0.049 & 0.053 & 0.058 & 0.068 \\
22,500 & 0.086 & 0.092 & 0.102 & 0.116 \\
40,000 & 0.132 & 0.152 & 0.172 & 0.197 \\
57,600 & 0.183 & 0.205 & 0.228 & 0.258 \\ \end{tabular}
\end{table}
Table 1: Running time in (sec).  
Figure 13: Dissolution effect under different evaporation rates, where the value in part (**a**) is ten times of that of the one in part (**b**).  
**Author Contributions:** Conceptualization, X.N., C.Z., Z.Y. and G.Y.; methodology, X.N., Z.Y. and G.Y.; software, X.N., C.Z. and Z.Y.; validation, X.N., C.Z. and G.Y.; formal analysis, X.N. and G.Y.; investigation, X.N., C.Z., Z.Y. and G.Y.; writing--original draft preparation, X.N., C.Z. and Z.Y.; writing--review and editing, X.N., C.Z. and G.Y.; visualization, C.Z. and Z.Y.; supervision, X.N. and G.Y.; project administration, X.N. and Z.Y.; funding acquisition, X.N. and G.Y. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the National Key R&D Program of China (Grant No. 2023 YFC3304000), the Beijing Municipal Science and Technology Program (Grant No. Z221100005222018), the Open Project Program of State Key Laboratory of Virtual Reality Technology and Systems, Beihang University (Grant No. VRLAB2023C02), and the Fundamental Research Funds for Central Universities (Grant No. BLX202142).  
**Institutional Review Board Statement:** Not applicable.  
**Data Availability Statement:** Data are unavailable due to privacy restrictions.  
**Conflicts of Interest:** The authors declare no conflicts of interest.