That’s pretty much how I handled the odd-shaped window in our attic. I tried to be precise at first—measuring angles, using a protractor, the whole deal—but honestly, it just got frustrating. Ended up doing almost exactly what you described: cardboard, pencil, and a bit of trial and error. It wasn’t perfect, but unless someone’s walking around with a flashlight looking for gaps, no one notices.
I get why people want everything to line up perfectly, but sometimes “close enough” is all you can expect with these weird shapes. Especially if you’re working alone and don’t have fancy tools. I do wonder if there’s some middle ground between the DIY cardboard method and hiring a custom installer... maybe 3D scanning or something? Though that sounds like overkill for most of us.
Anyway, if the blackout shade works and you’re happy with it, I’d call that a win. Perfection’s overrated when it comes to home projects like this.
I totally relate to the frustration—measuring those odd angles feels like a math class I didn’t sign up for. I actually tried using one of those angle finder apps, but it was more confusing than helpful. The cardboard method was way less stressful, even if it’s not perfect. I keep wondering if there’s some kind of template kit out there for this, or maybe something like peel-and-stick guides? 3D scanning sounds cool, but yeah, probably too much for most of us. At the end of the day, as long as it blocks light and looks decent, I’m not sweating the small gaps.
I’ve had my fair share of headaches with arched windows—ended up tracing the shape onto butcher paper and cutting a template. Not high-tech, but it worked better than any gadget I tried. Honestly, unless you’re after museum-level precision, close enough usually does the job.
Not high-tech, but it worked better than any gadget I tried.
That butcher paper trick brings back memories. I did something similar when we replaced the old leaded glass in our 1920s bungalow. Tried a digital angle finder first—ended up more confused than when I started. In the end, tracing the arch onto cardboard gave me the best fit, even if it was a bit rough around the edges. Funny how sometimes low-tech just wins out over all those gadgets. I get wanting precision, but like you said, unless you’re restoring a cathedral, “close enough” holds up just fine for most homes.
I get where you’re coming from—sometimes the old-school way just feels right, and for quick projects, it usually gets you close enough. But I’ll be honest, after years of patching up “almost perfect” fits, I’ve started leaning more on those digital gadgets. The learning curve is real, but once you get the hang of them, they save a ton of time (and headaches) when you need to match multiple arches or weird angles. Not saying cardboard is out, but for jobs where gaps really matter—like custom window inserts or trim—I’d rather wrestle with tech than redo a piece twice. Just my two cents...
I hear you on the digital gadgets making life easier—my cousin swears by his laser measurer and honestly, his projects always fit together like a puzzle. But I’ll admit, I still get a weird satisfaction out of tracing stuff with cardboard or that old cereal box from the recycling bin. There’s something kind of fun (and a little ridiculous) about crawling around with scissors and tape, trying to get that arch just right.
That said, I’ve had my share of “almost fits” turn into “why is there a draft in July?” situations. The last time I tried to DIY a window insert for our attic triangle window, I thought I nailed it… until the first rainstorm and suddenly it was like Niagara Falls in the corner. After that, I caved and borrowed my neighbor’s digital angle finder thingy. Not gonna lie, it felt like cheating at first, but wow—it saved so much time and swearing.
I still keep some cardboard handy for quick fixes or when I’m not feeling up for tech, but if I really care about getting it right (like with trim or anything that’s going to be visible), the gadgets are hard to beat. Plus, if you mess up digitally, at least you can blame the batteries or the app instead of your own eyesight.
Price is a thing though. Those tools aren’t cheap, especially if you’re only doing one or two windows. If you’ve got a neighbor who’s into this stuff already, maybe trade them some baked goods for borrowing their gear? That’s what I did—banana bread is basically DIY currency around here.
Anyway, both ways have their place. I guess it depends if you want to spend your Saturday measuring twice or cutting twice…