Morphogenesis of extant colonial Scleractinia and their habitat information are crucial for understanding the palaeoenvironmental conditions for fossil equivalents. Scleractinian morphogenesis has been studied mainly in light of the external environmental factors. Very recently, it is clear that the colonial dendrophyllid Scleractinia bud under the specific internal regularities and exhibit a variety of growth forms. For the purpose of simulating colonial form variations according to the changes in internal factors, morphogenesis of dendrophylliid Scleractinia is modelled in consideration with these regularities of budding. The system “Coral Simulator”, which generates and visualizes the model of corallites, is developed. By regulating three parameters (the interval of budding, the budding orientation, and the inclination of budding) which affect the colonial morphology, various colonial forms are generated. In the simulated models, two apparently different types of morphologies of extant dendrophylliids are found. The volume, the projected area, and the centre of gravity of the individual models can be calculated easily by this system.