Houdini的CHOP中基于点的变化Point-Based Variation in Houdini’s CHOPs

In this video we will look at how to add point-based variation to SOP level keyframe animation in Houdini’s CHOP networks. Along the way, we will also look at how to blend point attributes and how to generate displacement from our keyframe animation.

The Channel Wrangle code from CG Wiki:

tokeru.com/cgwiki/index.php?title=HoudiniChops#Stagger_channels_with_a_wrangle

Overlay Blend Mode on Wikipedia:

en.wikipedia.org/wiki/Blend_modes#Overlay

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00:37 Setting up the basic geometry

01:45 Creating the basic animation

02:34 Importing the point position animation into a CHOP net and adding a Spring CHOP

04:21 Re-importing the CHOP data into the SOP context

05:30 Setting up the point based variation with a radial gradient

09:34 Importing the offset data into the CHOP net

10:30 Summing up the approach for offsetting the point position animation

11:21 Taking a look at the Channel Wrangle snippet on CG Wiki

12:49 Creating the point-based animation offset with a Channel Wrangle

19:43 Adding some more variation in the map with a linear gradient

21:05 Blending the two maps by multiplying the values

24:05 Adding more variation with a noise from a texture map

26:31 Blending the noise with the two gradients using the “Overlay” blend mode

27:27 Creating the Overlay blend mode in an Attribute Wrangle

30:49 Checking the animation and adjusting the amount of the noise

32:48 Generating the vertical displacement for the stylized reflections

34:16 Setting up the Time Shift SOPs and calculating the distances

38:15 Deriving the displacement from the distances

40:22 Setting up the ramp to shape the displacement

42:03 Retrieving our original animation

43:30 Moving the calculations from above into one single Attribute Wrangle

44:05 Taking a quick look at the render setup

45:12 Summary

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Recorded in Houdini 16.5.405
在本视频中，我们将了解如何在Houdini的CHOP网络中为SOP级关键帧动画添加基于点的变化。在此过程中，我们还将研究如何混合点属性以及如何从关键帧动画生成位移。

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00:37设置基本几何体

01:45创建基本动画

02:34将点位置动画导入CHOP网并添加Spring CHOP

04:21将CHOP数据重新导入SOP上下文

05:30使用径向渐变设置基于点的变化

09:34将偏移数据导入CHOP网

10:30总结偏移点位置动画的方法

11:21看一下CG Wiki上的Channel Wrangle片段

12:49使用Channel Wrangle创建基于点的动画偏移

19:43使用线性渐变在地图中添加更多变化

21:05通过乘以值来混合两个地图

24:05使用纹理贴图中的噪点添加更多变化

26:31使用“叠加”混合模式将噪点与两个渐变混合

27:27在Attribute Wrangle中创建叠加混合模式

30:49检查动画并调整噪音量

32:48为风格化反射生成垂直位移

34:16设置时移SOP并计算距离

38:15从距离中获得位移

40:22设置坡道以塑造位移

42:03检索原始动画

43:30将上面的计算移动到一个属性Wrangle中

44:05快速查看渲染设置

45:12摘要

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录于Houdini 16.5.405