This week I learned and made the dissipation effects, the particles follow the smoke, and the model damage effects. Obviously, these effects require a lot of computer calculations. A long part of the learning process is spent waiting for calculations. The following is an introduction to the learning process of the three effects.
Test 1
The test is to make an object dissipate. The first stage of dissipate is the same as the first stage of object damage where the voronoi is needed to divide the object into multiple small fragments. The nodes in the figure below are nodes inside the DOP, which are used to detect the physical properties of the model. But the test result is that there is no gravity.
Torus did not move after adding gravity. It is because the model is not packed.
The solution is to add an assemble node and check the Create Packed Geometry command. The following is the display effect:
Next is the production of Torus’s dissipation effect from left to right. First of all, let me introduce some nodes:
In the DOPnet node rigidbodysolver includes bulletrbdsolver.
Multisolver can combine multiple different types of solvers to work together.
Create an active group and static group before making a left-to-right dissipation effect. Adding! before STATIC group!, Represents all parts except STATIC group. The display effect is as follows:
另一种分组方式，如图所示，我们可以通过noise来将point赋予0和1的值。其中1代表actice group。
Another way of grouping, as shown in the figure, we can assign points to values of 0 and 1 through noise. Where 1 represents actice group.
It can be seen from the above figure that the model is dissipating in the white area of the particle.
The purpose of the Fit, add, clamp and floatpoint node is to change all the points to 0 and 1. And expose the parameters of the add node, which can make all the points switch back and forth between 0 and 1, and make animations.
The following is the dissipation effect after set the frame.
The next step is to gradually reduce the dissipated small pieces, so an SOP solver needs to be added.
The role of Attribpromote is to create a prim attribute. The role of primitive is to narrow the selected group.
The final step is to hide the smaller particles.
When the value of the tokeep attribute is less than 0.1, the fragments will disappear automatically.
So far, the effect of dissipating objects has been completed. We can replace some other objects. The following is what I replaced with a monster model I made before.
Test2
The second test is to make a particle follow the smoke effect. The first is to make a smoke.
To make it easier to observe, we can create two lights to illuminate the smoke.
The following is the display effect of smoke.
Before creating the particles, we need to simulate the smoke first.
The role of the popadvectbyvolume node is to let particles follow volume.
The following is the display effect of particle.
After that, we need to convert the particles to sphere so that the particles can be rendered. The required node is copytopoint. The following is the display effect of the final result.
Test3
The last test is to make an effect that the meteorite explodes after hitting the building. But because only half of the work was made this week.
After getting the model, we need to clean up the model.
Introduction to clean model nodes:
- fuse: This node is often used to process and merge adjacent points.
- divide: The remove shared edges command of this node is used to delete shared edges, and it can also detect whether the model needs to be cleaned up.
- facet: In order to solve the point after dissolving the broken tuning, you need to use the remove innline point command in this node.
- polyfill: automatically fill the hole.
- .clean: The fix overlap command can repair the overlapped part
- boolean: Union command can melt the overlapping part.
Model reduction polyreduce This node can quickly convert high polygon to low polygon, but sometimes the model will be damaged and the shape will be broken.
Another reduceface method is the combination of vdbfromepolygons and convertvdb. We can get a cleaned model and the shape is more accurate.
The third method of reduceface is the project model. Which needs to use the ray node, and need to create a sphere polygon. Need to pay attention to the connection method of the node port as shown in the figure above.
The role of extracttransform is to transfer the motion of one model to another. Inport01 is the information of the first key frame entered, and inport02 is the complete animation information. At the same time, the copy to point node is needed to link the model to be moved and the output animation information.
The role of pointdeform is also to assign the movement of one model to another model.
After the model is cleaned up, we need to pre-process the broken effect:
Test the simulation. If the normal is created in this way, each layer of the building will be split in the same way. This effect is not what we want.
The solution is as shown in the node link. The role of connectivity is to create a class attribute, and the role of the nodes in the yellow area is to divide the model into different groups. In this way, the fragmentation of voronoi between different groups will be different.
Later, I grouped buliding into different materials.
The role of normal is to adjust the smoothness of the model.
Broken problem: In the pre-processing voronoi effect, such a phenomenon of model damage often occurs.
This is a very time-consuming process, we need to adjust the data on the right side of the above figure to test. In addition, in order to facilitate the simulation, we can separate the groups with issues and adjust them separately.
At this point, this week’s practice department is over. In the process of learning, I always encounter some new nodes and forget the old ones. But the production itself is a good way to consolidate and review.