Hi, Before I begin, I'm a complete beginner to 3D modelling and HoudinFX so please try not to pull your hair after looking at my hipnc file attached. For my very first project (after following a donut tutorial from "Houdini is HIP" series) I decided to model my keyboard. I thought it'd be a simple design with a few boxes, but boy was I wrong!
After completing my design, when I added a light source, the entire geometry turned dark! Since I've used Boolean SOP (Union and Subtract) in my design and as suggested online, I added a PolyDoctor SOP just before the last NULL node. Then went to its Visualize tab and turned Invalid Polygons on, and to my horror about 80% of my geometry went red!
I'm sure I must've made a thousand illegal moves and need a human (not AI) to point them out to me. Attaching my hipnc file and a few pictures below, hope it helps (you and me, both 🥲).
Hi, looking at your hip file I noticed the following:
- The size of your keyboard is 44 x 13 Units. The default size of an area light is 1 x 1 unit. A unit in Houdini can be anything you want but the default is 1 unit = 1 meter. So either scale up all lights or scale down your keyboard. - The Boolean on the KB_Body resulted with ngons. Your Polydoctor is highlighting the ngons in red. - In the KB_Keys, there was an error with your selection for the polybevel2 after the Boolean. It was missing some edges which resulted in an incomplete bevel. I've shown how you can use abseams from the Boolean as a procedural selection for the polybevel instead.
Personally, I prefer to model to scale rather than scale down/up at the end of the chain. In this example, I've scaled the keyboard down at the end and you'll notice that editing anything upstream will be at the original scale. This means any editing will require zooming out to see what you are doing and zooming in to preview the result.
I also prefer to model using the headlight and use Redshift for setting up the actual lights.
I've uploaded a hip file where my changes are coloured green.
Mad respect for putting in time and effort to point these things out to me! Thank you. 🫡
Fortunately, I figured out all of these things by scouring the internet and playing around. What I still don't get is how to fix all the ngons. I posted the same question on another platform and there I was told that they don't really matter so I ignored them for now.
Something else pointed out on that platform was "There are so many things wrong with how this was modeled that are fundamental." Yet nobody said what they were. I hope someone here is kind enough to do that.
Anyways, attaching the rendered version for you to be proud of me 😁
I wouldn`t say your modelling is wrong. That is not the case. You can model like you did with no problem. The question is always, what is your 3d model needed for? If you plan to stay in Houdini and render your keyboard there, as it is, your approach is absolutely fine. When you plan to deform your keyboard, for instance, as you want it to bend like rubber, your geometry will cause problems. If you plan to export it to a game engine, your fine bevels are a waste of polygons. In general, when people speak of correct modelling, they refer to subdivision modelling. A style of modeling where you create your object with the least amount of polygons as possible, and the ability to subdivide without problems. To test, you can add a subdivision SOP to your model and see what happens. Pure Subd Modelling also only allows quad and tri polygons.
Thank you, CYTE! Your reply is very insightful. It also has great pointers for me to explore further. My next challenge would be to recreate this from scratch but with no ngons this time.
