Master Box - Separate Corner Radius, In…: is this $14.99 stack worth it for Films?
If you’ve ever fought with the standard After Effects rectangle tool, you know the pain: you want a box that grows from a specific anchor point, not the center, and you want to round only the top-left corner while keeping the others sharp. Standard AE shape layers don’t handle that without a messy expression hack or a plugin you have to install. Master Box solves that exact friction. It’s a single .ffx preset from Motion Embassy that drops a fully controllable shape layer into your composition, letting you treat a rectangle like a UI element—with independent corner radii, anchor-based scaling, and side-trimming. For motion designers building interfaces, lower thirds, or abstract graphics, this $14.99 tool eliminates the “why is my box growing from the middle?” headache before it even starts.
Quick answer
| Best for | Motion designers who need precise, anchor-based rectangles with independent corner rounding in After Effects. |
| Skip if | You’re using an After Effects version older than CC 25.0.1 (2024) or don’t need per-corner control. |
| Price | $14.99 |
| Format | Single .ffx After Effects preset (7.65 KB) |
| One-line take | A lightweight preset that turns AE’s basic rectangle into a flexible, UI-ready shape with squircle support. |
What you’re actually buying
You’re not buying a heavy plugin or a suite of effects. You’re buying a 7.65 KB .ffx preset that installs in seconds and replaces the default rectangle tool with a smarter alternative. The core value is in the control: you can set the anchor point on the X and Y axes, meaning your box scales from that specific point rather than the center. This is critical for motion work where you’re animating a card sliding in from the left—you want it to grow or shrink from that left edge, not expand symmetrically. (Master Box - Separate)
Beyond positioning, the preset unlocks separated corner controls. Each corner has its own radius and profile settings, so you can make a box with three sharp corners and one rounded one, or vary the roundness across all four. You can switch between percentage-based and pixel-based radii, and use a “Corner Adjust” setting to create squircles—that smooth, Apple-style curvature that standard round corners can’t achieve. There are four corner profiles to choose from: concave, convex, flat, and step. If you’re designing modern UI animations or tech-themed graphics, that squircle control alone is worth the price. (Master Box - Separate)
The preset also lets you trim the box from all four sides independently, and even offset the X and Y position of each corner to create distorted, skewed shapes. Trimming still works even when corners are offset, which gives you a lot of creative freedom for abstract motion pieces. One buyer noted the developer’s responsiveness, calling it a “great product with an attentive developer. Highly recommend. ❤️” Gumroad reviews reflect that support, which matters when you’re troubleshooting a preset in a tight deadline.
Why it’s on our radar
This preset is interesting because it solves a specific, recurring pain point in After Effects without bloating your project. Most motion designers either live with the default rectangle’s limitations or install a full plugin suite for what is essentially a shape layer tweak. Master Box sits in the sweet spot: it’s a single file, no install, no license server, and it works with the JavaScript Expressions Engine that’s now standard in modern AE. The fact that it supports four corner profiles and squircle adjustments makes it more than a simple roundness tool—it’s a mini UI design system for your motion comps. For anyone building interface animations, product demos, or tech graphics, this is a niche tool that saves real time on every rectangle you create.
What actually matters
- Version compatibility: You need After Effects CC 25.0.1 (2024) or newer. If you’re on an older version, this preset won’t work. Check your AE version before buying. (Master Box - Separate)
- Expressions Engine: Your project must be set to use the JavaScript Expressions Engine. If you’re still on the legacy C++ engine, you’ll need to switch project settings. (Master Box - Separate)
- Anchor point behavior: The whole point is that size changes respect your anchor point. If you’re used to the default rectangle growing from the center, this will feel different at first—but that’s the feature, not a bug. (Master Box - Separate)
- Squircle control: The “Corner Adjust” setting is the standout. If you’re making modern, polished UI animations, test this out to see if the curvature matches your design language. (Master Box - Separate)
Mid-check
If you’re on a current version of After Effects and you’re tired of fighting the default rectangle tool, Master Box is a low-risk, high-utility add.
FAQ
Does Master Box work with the standard After Effects rectangle tool?
No, it’s a separate .ffx preset that creates its own shape layer. You apply it to a new layer or existing comp, and it gives you the enhanced controls. It doesn’t modify the default tool.
Can I use Master Box for pixel-perfect UI animations? Yes. The pixel-based radius option and anchor point control make it ideal for UI work. You can set exact pixel values for corner radii and position the box precisely where you need it.
What’s the difference between percentage-based and pixel-based corner radii? Pixel-based gives you exact control in pixels, which is great for UI design. Percentage-based scales the radius relative to the box size, which is useful if you’re animating the box’s dimensions and want the corners to stay proportional. (Master Box - Separate)
Does Master Box support squircles? Yes. The “Corner Adjust” setting lets you create squircles, which have a smoother, more organic curvature than standard round corners. This is a key feature for modern design aesthetics.
Is there a free trial or demo? The listing doesn’t mention a free trial. It’s a one-time purchase at $14.99. You can check the Master Box product page for any updated offers or previews.
Bottom line
If you’re a motion designer who uses After Effects for UI animations, lower thirds, or abstract graphics, Master Box is a smart, lightweight addition to your toolkit. It solves the anchor point and per-corner rounding problems that the default rectangle tool can’t handle, and it does so without the bloat of a full plugin. For $14.99, you’re getting a tool that will save you time on every rectangle you create—and the squircle control alone is worth the price for anyone aiming for a modern, polished look. If you’re on a current version of After Effects, this is an easy yes.