About SumiCAD

SumiCAD (墨CAD) is free BIM software for Japanese timber houses (木造住宅). You draw the house once as a 3D model, and the same model gives the plans, elevations and sections, timber-frame structure checks, 確認申請 permit sheets and estimates from Japanese makers' catalogues. It runs on Windows 10 and 11, in Japanese and English.

Who is it for?

Small builders (工務店), carpenters and design offices (設計事務所) in Japan who design and build wooden houses in the conventional post-and-beam method (在来軸組工法), from the first plan to the permit set and the estimate. It is made to be learned quickly by people who build, not only by CAD specialists.

How much does it cost?

The SumiCAD desktop app is free for everyone, with no account and no licence key. Firms that want to work together online can subscribe to SumiCAD Cloud: ¥1,000 a month including one editor, ¥500 a month for each extra editor, and free viewers and clients (tax included). See Pricing.

Does it do 壁量計算, 確認申請 and structural checks?

Yes for the checks a timber house needs under the prescriptive rules (仕様規定): SumiCAD checks the wall quantity (壁量計算), the wall balance (4分割法), the joint hardware (N値計算) and beam sizes, and prepares the 確認申請 permit sheets with pre-filing checks. SumiCAD's list of features does not include a full allowable-stress structural calculation (許容応力度計算). Permit documents made with SumiCAD must be checked and signed by a licensed architect (建築士).

What is SumiCAD Cloud?

An optional service for firms: the owner sets the AI assistant and the prices once, editors work on the same projects with a change log, carpenters and trades open the latest drawings on their phone, and clients walk through their house in 3D in the browser. See SumiCAD Cloud.

Who makes it?

SumiCAD is made by Mori no Takumi (森の匠), a builder of timber houses in Hokkaido. It started as the tool for our own work and is given away to every builder. Feature requests are welcome: ask for a feature, or see Contact and support.